Systems Operation

Usage:

Introduction

NOTE: For Specifications with illustrations, make reference to Specifications for 3406C Generator Set Engine Attachments, SENR1096. If the Specifications in SENR1096 are not the same as in the Systems Operation, Testing & Adjusting, look at the printing date on the cover of each book. Use the Specifications given in the book with the latest date.

Fuel System

2301A Electric Governor

Refer to 2301A Electric Governor Service Manual, SENR4676 for additional information.

The 2301A Electric Governor Control System consists of the components that follow: 2301A Electric Governor Control (EGC), actuator, Magnetic Pickup.

2301A Electric Governor Control (EGC)

The 2301A Electric Governor System gives precision engine speed control. The 2301A control measures engine speed constantly and makes necessary corrections to the engine fuel setting through an actuator connected to the fuel system.

(Typical Illustration) Magnetic Pickup Location
(1) Magnetic pickup. (2) Flywheel housing.

The engine speed is felt by a magnetic pickup. This pickup makes an AC voltage that is sent to the 2301A Control. The 2301A Control now sends a DC voltage signal to the actuator.

EG3P Actuator
(3) Actuator. (4) Actuator lever.

The actuator changes the electrical input from the 2301A Control to a mechanical output that is connected to the fuel system by linkage. For example, if the engine speed is more than the speed setting, the 2301A Control will decrease its output and the actuator will now move the linkage to decrease the fuel to the engine.

Magnetic Pickup

Schematic Of Magnetic Pickup
(1) Magnetic lines of force. (2) Wire coils. (3) Gap. (4) Pole piece. (5) Flywheel ring gear.

The magnetic pickup is a single pole, permanent magnet generator made of wire coils (2) around a permanent magnet pole piece (4). As the teeth of the flywheel ring gear (5) cut through the magnetic lines of force (1) around the pickup, an AC voltage is generated. The frequency of this voltage is directly proportional to engine speed.

This engine speed frequency signal (AC) is sent to the 2301A Control Box where a conversion is made to DC voltage. The DC signal is now sent on to control the actuator, and this voltage is inversely proportional to engine speed. This means that if engine speed increases, the voltage output to the actuator decreases. When engine speed decreases, the voltage output to the actuator increases.

Woodward PSG Governor

Typical Example Schematic Of PSG Governor
(1) Return spring. (2) Output shaft. (3) Output shaft lever. (4) Strut assembly. (5) Speeder spring. (6) Power piston. (7) Flyweights. (8) Needle valve. (9) Thrust bearing. (10) Pilot valve compensating land. (11) Buffer piston. (12) Pilot valve. (13) Pilot valve bushing. (14) Control ports. (A) Chamber. (B) Chamber.

Introduction

The Woodward PSG (Pressure compensated Simple Governor) can operate as an isochronous or a speed droop type governor. It uses engine lubrication oil, increased to a pressure of 1200 kPa (175 psi) by a gear type pump inside the governor, to give hydra/mechanical speed control.

Pilot Valve Operation

The governor is driven by the governor drive unit. This unit turns pilot valve bushing (13) clockwise as seen from the drive unit end of the governor. The pilot valve bushing is connected to a spring driven ballhead. Flyweights (7) are fastened to the ballhead by pivot pins. The centrifugal force caused by the rotation of the pilot valve bushing causes the flyweights to pivot out. This action of the flyweights changes the centrifugal force to axial force against speeder spring (5). There is a thrust bearing (9) between the toes of the flyweights and the seat for the speeder spring. Pilot valve (12) is fastened to the seat for the speeder spring. Movement of the pilot valve is controlled by the action of the flyweights against the force of the speeder spring.

The engine is at the governed (desired) rpm when the axial force of the flyweights is the same as the force of compression in the speeder spring. The flyweights will be in the position shown. Control ports (14) will be closed by the pilot valve.

Fuel Increase

PSG Governor Installed
(2) Output shaft. (15) Carburetor control linkage.

When the force of compression in the speeder spring increases (operator increases desired rpm) or the axial force of the flyweights decreases (load on the engine increases) the pilot valve will move in the direction of the drive unit. This opens control ports (14). Pressure oil flows through a passage in the base to chamber (B). The increased pressure in chamber (B) causes power piston (6) to move.

The power piston pushes strut assembly (4), that is connected to output shaft lever (3). The action of the output shaft lever causes counterclockwise rotation of output shaft (2). This moves carburetor control linkage (15) in the THROTTLE OPENED direction.

As the power piston moves in the direction of return spring (1) the volume of chamber (A) increases. The pressure in chamber (A) decreases. This pulls the oil from the chamber inside the power piston, above buffer piston (11) into chamber (A). As the oil moves out from above buffer piston (11) to fill chamber (A) the buffer piston moves up in the bore of the power piston. Chambers (A and B) are connected respectively to the chambers above and below the pilot valve compensating land (10). The pressure difference felt by the pilot valve compensating land adds to the axial force of the flyweights to move the pilot valve up and close the control ports. When the flow of pressure oil to chamber (B) stops so does the movement of the fuel control linkage.

Fuel Decrease

When the force of compression in the speeder spring decreases (operator decreases desired rpm) or the axial force of the flyweights increases (load on the engine decreases) the pilot valve will move in the direction of speeder spring (5). This opens control ports (14). Oil from chamber (B) and pressure oil from the pump will dump through the end of the pilot valve bushing. The decreased pressure in chamber (B) will let the power piston move in the direction of the drive unit. Return spring (1) pushes against strut assembly (4). This moves output shaft lever (3). The action of the output shaft lever causes clockwise rotation of output shaft (2). This moves carburetor control linkage (15) in the THROTTLE CLOSED direction.

Speed Adjustment

PSG Electric Governor
(1) Synchronizing motor. (2) Clutch assembly. (3) Link assembly. (4) Speeder spring. (5) Pilot valve.

On electric PSG governors, speed adjustments are made by a 24V DC reversible synchronizing motor (1). The motor is controlled by a switch that can be put in a remote location.

The synchronizing motor drives clutch assembly (2). The clutch assembly protects the motor if it is run against the adjustment stops.

When the clutch assembly is turned clockwise it pushes link assembly (3) against speeder spring (4). The force of compression in speeder spring (4) is increased. This causes pilot valve (5) to move toward governor drive unit; see Pilot Valve Operation. The engine will increase speed, then get stability at a new desired rpm.

When the clutch assembly is turned counterclockwise the link assembly moves away from speeder spring. The force of compression in the speeder spring is decreased. This causes the pilot valve to move away from governor drive unit. The engine will decrease speed, then get stability at a new desired rpm.

NOTE: The clutch assembly can be turned manually if necessary.

Speed Droop

Speed droop is the difference between no load rpm and full load rpm. This difference in rpm divided by the full load rpm and multiplied by 100 is the percent of speed droop.

PSG Governor (View A-A from previous illustration)
(3) Link assembly. (6) Pivot pin. (7) Output shafts. (8) Droop adjusting bracket. (9) Shaft assembly.

The speed droop of the PSG governor can be adjusted. The governor is isochronous when it is adjusted so that the no load and full load rpm is the same. Speed droop permits load division between two or more engines that drive generators connected in parallel or generators connected to a single shaft.

Speed droop adjustment on PSG governors is made by movement of pivot pin (6). When the pivot pin is put in alignment with output shafts (7), movement of the output shaft lever will not change the force of the speeder spring. When the force of the speeder spring is kept constant, the desired rpm will be kept constant. See Pilot Valve Operation. When the pivot pin is moved out of alignment with the output shafts, movement of the output shaft lever will change the force of the speeder spring proportional to the load on the engine. When the force of the speeder spring is changed, the desired rpm of the engine will change.

A droop adjusting bracket (8) outside the governor connected to pivot pin (6) by link assembly (3) and shaft assembly (9) is used to adjust speed droop.

524/1724 Electric Governor

Refer to 524/1724 Electrically Powered Governor Systems Service Manual, SENR6430 for additional information.

The 524/1724 Electric Governor System consists of the components that follow: 8290 Speed Control, 524/1724 Actuator and Magnetic Pickup.

8290 Speed Control

The 8290 Speed Control measures engine speed constantly and makes necessary corrections to the engine fuel setting through the actuator connected to the fuel system.

Engine speed is converted by the magnetic pickup into an AC voltage. This AC voltage is sent to the speed control where it is converted into a DC voltage that is used by the actuator to position the engine fuel rack.

524/1724 Actuator

The 524/1724 actuator changes the electrical input from the speed control to a mechanical output that is connected to the fuel system by linkage.

Basic 524/1724 Electric Powered Governor Schematic

Magnetic Pickup

Schematic Of Magnetic Pickup
(1) Magnetic lines of force. (2) Wire coils. (3) Gap. (4) Pole piece. (5) Flywheel ring gear.

The magnetic pickup is a single pole, permanent magnet generator made of wire coils (2) around a permanent magnet pole piece. As the teeth of the flywheel ring gear (5) cut through the magnetic lines of force (1) around the pickup, an AC voltage is generated. The frequency of this voltage is directly proportional to engine speed.

This engine speed frequency signal (AC) is sent to the speed control where a conversion is made to a DC voltage level.

Fuel Ratio Control

Fuel Ratio Control (Engine Started) (Typical Example)
(1) Inlet air chamber. (2) Diaphragm assembly. (3) Internal valve. (4) Oil drain passage. (5) Oil inlet. (6) Stem. (7) Spring. (8) Piston. (9) Oil passage. (10) Oil chamber. (11) Lever.

The fuel ratio control limits the amount of fuel to the cylinders during an increase of engine speed (acceleration) to reduce exhaust smoke. Properly adjusted it also minimizes the amount of soot in the engine.

Stem (6) moves lever (11) which will restrict the movement of the fuel rack in the FUEL ON direction only.

With the engine stopped, there is no oil pressure and stem (6) is in the fully extended position as in the (Engine Started) illustration. The movement of the fuel rack and lever (11) is not restricted by stem (6). This gives maximum fuel to the engine for easier starts.

When oil pressure arrives at the control, engine oil flows through oil inlet (5) into oil chamber (10). Piston (8) and stem (6) move to restrict lever and rack to the smoke limited rack setting.

Stem (6) will not move from the limited rack setting until inlet manifold pressure increases enough to move internal valve (3). A line connects the inlet manifold with inlet air chamber (1) of the fuel ratio control.

Fuel Ratio Control (Engine Acceleration) (Typical Example)
(1) Inlet air chamber. (2) Diaphragm assembly. (3) Internal valve. (4) Oil drain passage. (5) Oil inlet. (6) Stem. (7) Spring. (8) Piston. (9) Oil passage. (10) Oil chamber. (11) Lever.

When the governor control is moved to increase fuel to the engine, stem (6) limits the movement of lever (11) in the FUEL ON direction. The oil in oil chamber (10) acts as a restriction to the movement of stem (6) until inlet air pressure increases.

As the inlet air pressure increases, diaphragm assembly (2) and internal valve (3) move to the right. The internal valve opens oil passage (9), and oil in oil chamber (10) goes to oil drain passage (4). With the oil pressure reduced behind piston (8), spring (7) moves the piston and stem (6) to the right. Piston (8) and stem (6) will move until oil passage (9) is closed by internal valve (3). Lever (11) can now move to let the fuel rack go to the full fuel position. The fuel ratio control is designed to restrict the fuel until the air pressure in the inlet manifold is high enough for complete combustion. It prevents large amounts of exhaust smoke caused by an air/fuel mixture with too much fuel.

Fuel Pump Mechanical Drive

Fuel Pump Mechanical Drive
(1) Bolt. (2) Position ring. (3) Gear. (4) Position ring. (5) Carrier assembly. (6) Fuel injection pump camshaft.

The fuel pump drive group connects the drive end of the fuel injection pump camshaft with the timing gears in the front of the engine. The unit uses engine oil pressure to hold the carrier assembly (5) against the end of the camshaft. The carrier assembly does not slide during engine operation. There is no advance of injection timing.

The drive group is connected to the fuel injection pump camshaft. Bolts (1), position ring (2) and position ring (4) hold gear (3) together. Carrier assembly (5) has two splines. The splines of position ring (2) and the inner helical splines are in contact with the helical splines on the fuel injection pump camshaft (6). When the engine is started, gear (3) drives fuel injection pump camshaft (6) through position ring (2) and carrier assembly (5).

Electrical System

Engine Electrical System

The electrical system can have three separate circuits: the charging circuit, the starting circuit and the low amperage circuit. Some of the electrical system components are used in more than one circuit. The battery (batteries), circuit breaker, ammeter, cables and wires from the battery are all common in each of the circuits.

The charging circuit is in operation when the engine is running. An alternator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output to keep the battery at full charge.

The starting circuit is in operation only when the start switch is activated.

The low amperage circuit and the charging circuit are both connected through the ammeter. The starting circuit is not connected through the ammeter.

Grounding Practices

Proper grounding for machine and engine electrical systems is necessary for proper machine performance and reliability. Improper grounding will result in uncontrolled and unreliable electrical circuit paths which can result in damage to main bearings and crankshaft journal surfaces.

To insure proper functioning of the engine electrical systems, an engine-to-frame ground strap with a direct path to the battery must be used. This may be provided by way of a starting motor, a frame to starting motor ground, or a direct frame to engine ground.

Ground wires/straps should be combined at ground studs dedicated for ground use only. The engine alternator must be battery (-) grounded with a wire size adequate to handle full alternator charging current.

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NOTICE

This engine may be equipped with a 12 or 24 volt starting system. Use only equal voltage for boost starting. The use of a welder or higher voltage will damage the electrical system.

Charging System Components

Alternator (4N3986, 4N3987, 5N5692, 3T6352, And 7G7889)

The alternator is driven by belts from the crankshaft pulley. This alternator is a three phase, self-rectifying charging unit, and the regulator is part of the alternator.

This alternator design has no need for slip rings or brushes, and the only part that has movement is the rotor assembly. All conductors that carry current are stationary. The conductors are: the field winding, stator windings, six rectifying diodes, and the regulator circuit components.

The rotor assembly has many magnetic poles like fingers with air space between each opposite pole. The poles have residual magnetism (like permanent magnets) that produce a small amount of magnet-like lines of force (magnetic field) between the poles. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings from the small magnetic lines of force made by the residual magnetism of the poles. This AC current is changed to direct current (DC) when it passes through the diodes of the rectifier bridge. Most of this current goes to charge the battery and to supply the low amperage circuit, and the remainder is sent on to the field windings. The DC current flow through the field windings (wires around an iron core) now increases the strength of the magnetic lines of force. These stronger lines of force now increase the amount of AC current produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator.

The voltage regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system and switches on and off many times a second to control the field current (DC current to the field windings) for the alternator to make the needed voltage output.

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NOTICE

Never operate the alternator without the battery in the circuit. Making or breaking an alternator connection with heavy load on the circuit can cause damage to the regulator.

Alternator Components (Typical Example)
(1) Regulator. (2) Roller bearing. (3) Stator winding. (4) Ball bearing. (5) Rectifier bridge. (6) Field winding. (7) Rotor assembly. (8) Fan.

Alternator (7N9720)

The alternator is driven by V-belts from the crankshaft pulley. This alternator is a three phase, self-rectifying charging unit, and the regulator is part of the alternator.

Alternator Components (Typical Example)
(1) Fan. (2) Stator winding. (3) Field winding. (4) Regulator. (5) Ball bearing. (6) Roller bearing. (7) Rotor assembly. (8) Rectifier assembly.

The rotor assembly has many magnetic poles like fingers with air space between each opposite pole. The poles have residual magnetism (like permanent magnets) that produce a small amount of magnet-like lines of force (magnetic field) between the poles. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings from the small magnetic lines of force made by the residual magnetism of the poles. This AC current is changed to direct current (DC) when it passes through the diodes of the rectifier bridge. Most of this current goes to charge the battery and to supply the low amperage circuit, and the remainder is sent onto the field windings. The DC current flow through the field windings (wires around an iron core) now increases the strength of the magnetic lines of force. These stronger lines of force now increase the amount of AC current produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator.

Alternator (9G4574)

This alternator has three-phase, full-wave rectified output. It is brushless. The rotor and bearings are the only moving parts.

Alternator Components (Typical Example)
(1) Fan. (2) Front frame assembly. (3) Stator assembly. (4) Rotor assembly. (5) Field winding. (6) Regulator assembly. (7) Condenser (suppression capacitor). (8) Rectifier assembly. (9) Rear frame assembly.

When the engine is started and the rotor turns inside the stator windings, three-phase alternating current (AC) and/or rapidly rising voltage is generated.

A small amount of alternating current (AC) is changed (rectified) to pulsating direct current (DC) by the exciter diodes on the rectifier assembly. Output current from these diodes adds to the initial current which flows through the rotor field windings from residual magnetism. This will make the rotor a strong magnet and cause the alternator to become activated automatically. As rotor speed, current and voltages increase, the rotor field current increases enough until the alternator becomes fully activated.

The main battery charging current is charged (rectified) from AC to DC by the other positive and negative diodes in the rectifier and pack (main output diodes) which operate in a full wave linkage rectifier circuit.

The voltage regulator is a solid state (transistor, no moving parts) electronic switch. It feels the voltage in the system and gives the necessary field current (current in the field windings of the alternator) for the alternator to make the needed voltage. The voltage regulator controls the field current to the alternator by switching on and off many times a second. There is no voltage adjustment for this regulator.

The regulator is fastened to the alternator by two different methods. One method fastens the regulator to the top, rear of alternator. With the other method the regulator is fastened separately by use of a wire and a connector that goes into the alternator.

Alternator (6T1395)

Alternator Components (Typical Example)
(1) Slip rings. (2) Fan. (3) Stator assembly. (4) Rotor assembly. (5) Brush and holder assembly.

The alternator is a three phase, self-rectifying charging unit that is driven by V-belts. The only part of the alternator that has movement is the rotor assembly. Rotor assembly (4) is held in position by a ball bearing at each end of the rotor shaft.

The alternator is made up of a front frame at the drive end, rotor assembly (4), stator assembly (3), rectifier assembly, brushes and holder assembly (5), slip rings (1) and rear end frame. Fan (2) provides heat removal by the movement of air through the alternator.

Rotor assembly (4) has field windings (wires around an iron core) that make magnetic lines of force when direct current (DC) flows through them. As the rotor assembly turns, the magnetic lines of force are broken by stator assembly (3). This makes alternating current (AC) in the stator. The rectifier assembly has diodes that change the alternating current (AC) from the stator to direct current (DC). Most of the DC current goes to charge the battery and make a supply for the low amperage circuit. The remainder of the DC current is sent to the field windings through the brushes.

Starting System Components

Solenoid

Typical Example

A solenoid is a magnetic switch that does two basic operations.

a. Closes the high current starting motor circuit with a low current start switch circuit.

b. Engages the starting motor pinion with the ring gear.

The solenoid switch is made of an electromagnet (one to two sets of windings) around a hollow cylinder. There is a plunger (core) with a spring load inside the cylinder that can move forward and backward. When the start switch is closed and electricity is sent through the windings, a magnetic field is made that pulls the plunger forward in the cylinder. This moves the shift lever (connected to the rear of the plunger) to engage the pinion drive gear with the ring gear. The front end of the plunger then makes contact across the battery and motor terminals of the solenoid, and the starting motor begins to turn the flywheel of the engine.

When the start switch is opened, current no longer flows through the windings. The spring now pushes the plunger back to the original position, and at the same time, moves the pinion gear away from the flywheel.

When two sets of windings in the solenoid are used, they are called the hold-in winding and the pull-in winding. Both have the same number of turns around the cylinder, but the pull-in winding uses a larger diameter wire to produce a greater magnetic field. When the start switch is closed, part of the current flows from the battery through the hold-in winding, and the rest flows through the pull-in windings to the motor terminal, then through the motor to ground. When the solenoid is fully activated (connection across battery and motor terminal is complete), current is shut off through the pull-in windings. Now only the smaller hold-in windings are in operation for the extended period of time it takes to start the engine. The solenoid will now take less current from the battery, and heat made by the solenoid will be kept at an acceptable level.

Starting Motor

The starting motor is used to turn the engine flywheel fast enough to get the engine to start running.

The starting motor has a solenoid. When the start switch is activated, the solenoid will move the starting motor pinion to engage it with the ring gear on the flywheel of the engine. The starting motor pinion will engage with the ring gear before the electric contacts in the solenoid close the circuit between the battery and the starting motor. When the circuit between the battery and the starting motor is complete, the pinion will turn the engine flywheel. A clutch gives protection for the starting motor so that the engine can not turn the starting motor too fast. When the start switch is released, the starting motor pinion will move away from the ring gear.

Starting Motor Cross Section (Typical Example)
(1) Field. (2) Solenoid. (3) Clutch. (4) Pinion. (5) Commutator. (6) Brush Assembly. (7) Armature.

Other Components

Circuit Breaker

Circuit Breaker Schematic
(1) Reset button. (2) Disc in open position. (3) Contacts. (4) Disc. (5) Battery circuit terminals.

The circuit breaker is a switch that opens the battery circuit if the current in the electrical system goes higher than the rating of the circuit breaker.

A heat activated metal disc with a contact point makes complete the electric current through the circuit breaker. If the current in the electrical system gets too high, it causes the metal disc to get hot. This heat causes a distortion of the metal disc which opens the contacts and breaks the circuit. A circuit breaker that is open can be reset (an adjustment to make the circuit complete again) after it becomes cool. Push the reset button to close the contacts and reset the circuit breaker.

Shutoff Solenoid

The rack shutoff solenoid, when activated, moves the shutoff lever in the governor housing which in turn moves the fuel rack to the fuel closed position. The solenoid is activated by a manual control switch.

Fuel Pressure Switch

A fuel pressure switch is used in all systems with an external regulator. The switch prevents current discharge (field excitation) to alternator from the battery when the engine is not in operation. In systems were the regulator is part of the alternator, the transistor circuit prevents current discharge to the alternator and the fuel pressure switch is not required.

Wiring Diagrams

Many types of electrical systems are available for these engines. Some charging systems use an alternator and a regulator in the wiring circuit. Others have the regulator inside the alternator.

A fuel or oil pressure switch is used in all systems with an external regulator. The switch prevents current discharge (field excitation) to alternator from the battery when the engine is not in operation. In the systems where the regulator is part of the alternator, the transistor circuit prevents current discharge to the alternator and the fuel or oil pressure switch is not required.

All wiring schematics are usable with 12, 24, 30 or 32 volts unless the title gives a specific description.

NOTE: Wire and cable shown dotted on wiring diagrams is to be supplied by customer. The charts that follow gives the correct wire sizes and color codes. The abbreviations given below are used with the wiring diagrams in this section.

The present type of wire identification, used on all Caterpillar equipment uses only eleven solid colors.

In addition to only eleven basic colors of wire, a circuit number is stamped (put) on each wire. The circuit number is stamped approximately every inch for the length of the wire. The identification number for a circuit will be the same for any Caterpillar equipment.

For example: A color code of "A701-GY" on the schematic would mean, there is a gray wire with the circuit number "A701" stamped on it. This wire is the solenoid signal wire (power) for cylinder #1 (CYLINDER HEAD SOL 1) on the Electronic Unit Injector (EUI) system wire harness. The "A701-GY" color code will be the identification of "SOLENOID 1 POWER" circuit on all Caterpillar equipment wire harnesses with Electronic Unit Injector (EUI) systems.

Another wire identification on the schematic is the size of the wire. The size or gauge of the wire is called "AWG". The gauge of the wire will follow the wire color.

For example: A color code of "150-OR-14" on the schematic would indicate the "150-OR" wire is a 14 AWG wire.

If the gauge of wire is not listed after the wire color, the gauge of the wire will be 16 AWG.

Grounded Electrical Systems

These systems are used in applications when it is not necessary to prevent radio distortion and/or chemical changes (electrolysis) of grounded components

Regulator Inside Alternator

Charging System
(1) Ammeter. (2) Alternator. (3) Battery.

Charging System with Electric Starting Motor
(1) Start switch. (2) Ammeter. (3) Alternator. (4) Battery. (5) Starting motor.

Regulator Separate From Alternator

Charging System
(1) Ammeter. (2) Regulator. (3) Pressure switch (N/O). (4) Resistor (used with 30 and 32V systems). (5) Battery. (6) Alternator.

Charging System with Electric Starting Motor
(1) Start switch. (2) Ammeter. (3) Regulator. (4) Resistor (for 30 and 32V systems). (5) Battery. (6) Starting motor. (7) Pressure switch (N/O). (8) Alternator.

Alternator-Off Engine

The following diagrams are for use only when an alternator or charging generator is not used in the engine electrical system.

System with One Starting Motor
(1) Start switch. (2) Starting motor. (3) Battery.

Insulated Electrical Systems

These systems are most often used in applications where radio interference is not desired or where conditions are such that grounded components will have corrosion from chemical change (electrolysis).

Regulator Inside Alternator

Charging System
(1) Ammeter. (2) Alternator. (3) Battery.

Charging System with Electric Starting Motor
(1) Start switch. (2) Ammeter. (3) Alternator. (4) Battery. (5) Starting motor.

Regulator Separate From Alternator

Charging System
(1) Ammeter. (2) Regulator. (3) Pressure switch (N/O). (4) Resistor (used with 30V and 32V systems). (5) Battery. (6) Alternator.

Alternator-Off Engine

The following diagrams are for use only when an alternator or charging generator is not used in the engine electrical system.

System with One Starting Motor
(1) Start switch. (2) Starting motor. (3) Battery.

Electric Tachometer Wiring

(1) Magnetic pickup. (2) Terminal Connections (terminals 18 and 19 on load sharing governor control and terminals 7 and 8 on standby governor control). (3) Tachometer. (4) Ground connection (governor control chassis ground). (5) Governor control terminal strip. (6) Wiring connections (for second tachometer circuit if needed). (7) All wire must be 22AWG shielded cable or larger. (8) Dual speed switch terminal strip. (9) Ground connection (ground to engine).

Automatic Start/Stop System - Non-Package Generator Sets

Automatic Start/Stop System Schematic (Hydraulic Governor)
(1) Starting motor and solenoid. (2) Shutoff solenoid. (3) Fuel pressure switch. (4) Water temperature switch. (5) Oil pressure switch. (6) Overspeed contactor. (7) Battery. (8) Low lubricating oil pressure light (OPL). (9) Overcrank light (OCL). (10) Overspeed light (OSL). (11) High water temperature light (WTL). (12) Automatic control switch (ACS).

Automatic Start/Stop System Schematic (2301A Control System)
(1) Magnetic pickup. (2) Starting motor and solenoid. (4) Oil pressure switch 1 (OPS1). (5) Water temperature switch. (7) Overspeed switch. (8) Battery. (9) Low lubricating oil pressure light (OPL). (10) Overcrank light (OCL). (11) Overspeed light (OSL). (12) High water temperature light (WTL). (13) Automatic control switch (ACS). (14) EG-3P Actuator. (15) 2301A Control Box. (16) Oil pressure switch 2 (OPS2).

An automatic start/stop system is used when a standby electric set has to give power to a system if the normal (commercial) power supply has a failure. There are three main sections in the system. They are: the automatic transfer switch, the start/stop control panel (part of switch gear) and the electric set.

Automatic Transfer Switch

Automatic Transfer Switch (ATS)
(1) E1, E2, and E3 input to ATS from emergency source. (2) N1, N2 and N3 input to ATS from normal source. (3) T1, T2 and T3 output from ATS to the load. (4) Transfer mechanism.

The automatic transfer switch normally connects the 3-phase normal (commercial) power supply to the load. When the commercial power supply has a failure the switch will transfer the load to the standby electric set. The transfer switch will not transfer the load from commercial to emergency power until the emergency power gets to the rate voltage and frequency. The reason for this is, the solenoid that causes the transfer of power operates on the voltage from the standby electric set. When the normal power returns to he rated voltage and frequency and the time delay (if so equipped) is over, the transfer switch will return the load to the normal power supply.

Control Panel

Automatic Start/Stop Control Panel
(1) Overcrank light (OCL). (2) Low lubricating oil pressure light (OPL). (3) Overspeed light (OSL). (4) Automatic control switch (ACS). (5) High water temperature light (WTL).

The main function of the control panel is to control the start and shutoff of the engine.

The engine control on the automatic start/stop control panel is an automatic control switch (ACS) with four positions. The positions of switch (4) are: OFF/RESET, AUTO, MAN and STOP. Each light (1), (2), (3) and (5) goes ON only when a not normal condition in the engine stops the engine. The light for the condition that stopped the engine will stay ON even after the engine has stopped. Switch (4) must be moved to the OFF/RESET position for the light to go OFF. Each light will go ON, for a light test, when the light is pushed in and held in.

When the generator is to be used as a standby electric power unit, the automatic control switch is put in the AUTO position. Now, if the normal (commercial) electric power stops, the engine starts and the generator takes the electric load automatically. When the normal (commercial) electric power is ON again, for the electric load, the circuit breaker for the generator electric power automatically opens and the generator goes off the electric load. After the circuit breaker for the generator opens, the engine automatically stops.

When the automatic control switch (ACS) is moved to the MAN position, the engine starts. It is now necessary for the circuit breaker for the generator electric power to be closed manually. If the generator is a standby electric power unit and the automatic control switch (ACS) is in the MAN position when normal (commercial) electric power is ON again, the generator circuit breaker opens and the engine stops automatically the same as when the switch (ACS) is in the AUTO position.

The engine will stop with the automatic control switch (ACS) in either the AUTO or MAN positions if there is a not normal condition in the engine. The not normal condition in the engine that can stop the engine is either low lubricating oil pressure, high engine coolant (water) temperature or engine overspeed (too much rpm). When any of these conditions stops the engine, the light for the not normal condition will stay ON after the engine is stopped. The fourth not normal condition light is ON only when the starting motor runs the amount of seconds for the overcrank timer (engine does not start).

Move the automatic control switch (ACS) to the OFF/RESET position and the not normal condition lights go OFF.

Electric Set

The components of the electric set are: the engine, the generator, the starting motor, the battery, the shutoff solenoid and signal switches on the engine. The electric set gives emergency power to drive the load.

An explanation of each of the signal components is given in separate topics.

Wiring Diagrams

The following wiring diagrams are complete to show the connections of the automatic start/stop components with the engine terminal strip (TSI). The diagrams show all available options for both the hydraulic governor application and the 2301A Control System application.

For a more complete explanation of operation of the automatic start/stop system, refer to Floor Standing Switchgear SENR7970.

Automatic Start/Stop Wiring

Component Abbreviations

A-DC Ammeter

ACS-Engine Control Switch

ALT-Charging Alternator

AR-Arming Relay

ARX-Auxiliary Relay

ASO-Air Shutoff Solenoid

CB-Circuit Breaker

CCM-Cycle Cranking Module

CCT-Cycle Crank Relay

CDT-Cool Down Timer

CDTR-Cool Down Timer Relay

CRC-Cycle Crank Logic Timer

CTS-Crank Terminate Switch

DSS-Dual Speed Switch (Includes CTS And OSS)

GS-Governor Switch

GSM-Governor Synchronizing Motor

I-Initiate Contact (Remote Start)

MS-Magnetic Switch (Crank Circuit)

OCR-Overcrank Relay

OCT-Overcrank Timer

OP-Oil Pressure Indicator Sender

OPG-Oil Pressure Indicator

OPR-Low Oil Pressure Relay

OPS- Oil Pressure Switch

OPT-Optional Equipment

OSR- Overspeed Relay (In DSS)

PIL-Panel Illumination Lamp

PLS-Panel Lamp Switch

PS-Pinion Solenoid

RR-Run Relay

SS-Shutoff Solenoid

SM-Starting Motor

TDR-Time Delay Relay

TDX-Time Delay Auxiliary Relay

WT-Water Temperature Indicator Sender

WTG-Water Temperature Indicator

WTR-High Water Temperature Relay

WTS-Water Temperature Switch

^*-Indicates Equipment External To Control Panel

0-Terminal Strip Point (Control Panel)

[ ]-Terminal Strip Point (Generator Terminal Box)

[]-Relay Contact Line Number

Control Panel Wiring Schematic

NOTE A: Terminals 13 and 14 of the generator box will be connected to terminals 13 and 14 of the control panel when the CDT is not supplied.

Note B: Red jumper wire from terminal strip point number 4A to 4 in control panel must be removed when the cycle cranking module (CCM) is used.

NOTE C: Auxiliary relay (ARX) contacts are to be customer wired. See Relay Contact Schematic.

NOTE D: Dotted lines shown on Control Panel Wiring Schematic show engine wiring.

NOTE E: The overcrank timer (OCT) is to be adjusted to the 30 second setpoint (red dot). When cycle cranking (CCM) is used the overcrank timer (OCT) is to be adjusted to the 90 second setpoint (white dot).

NOTE F: ACS switch contacts shown with switch in auto position.

NOTE G: Jumper wire from terminal 72 to terminal 73 must be removed when DC ammeter (A) is used.

NOTE H: Jumper wire from terminal 13 to terminal 133 to be removed if additional fault shutdowns are added. Examples: reverse power relay or remote shutdown. Insert a normally closed switch between terminal 13 and terminal 133.

Automatic Start/Stop Wiring For Non-Package Generator Set

Used with Hydra Mechanical Governors

For wire sizes and color codes see the chart at the front of Wiring Diagrams section.

Wires and cables shown as dotted lines are customer supplied wiring.

Starting System with One Starting Motor
(1) Magnetic switch. (2) Circuit breaker. (3) Starting motor. (4) Battery. (5) Circuit breaker. (6) Terminal strip (on engine).

Dual Speed Switch
(7) Magnetic pickup. (8) Dual speed switch. (9) Time delay relay. (10) Oil pressure switch. (11) Governor synchronizing motor. (12) Water temperature switch.

Shutoff Solenoids
(13) Circuit breaker. (14) Rack shutoff solenoids. (15) Diode.

Automatic Start/Stop System Schematic

Automatic Start/Stop Wiring For Non-Package Generator Set

For wire sizes and color codes see the chart at the front of Wiring Diagrams section.

Wires and cables shown as dotted lines are customer supplied wiring.

Starting System With One Starting Motor
(1) Magnetic switch. (2) Circuit breaker. (3) Starting motor. (4) Battery. (5) Circuit breaker. (6) Terminal strip.

System Components
(1) Oil pressure contactor. (8) Dual speed switch. (9) Governor actuator. (10) Time delay relay. (11) Magnetic pickup. (12) Oil pressure switch. (13) Water temperature switch.

NOTE A: For standby operation - magnetic pickup (MP) and oil pressure contactor (OPS) must be wired to governor control with two conductor shielded cable (Beldon Mfg. Co. type 8780 or equivalent). (MP) should be connected to terminals 7 and 8 on governor control assembly and (OPS) should be connected to terminals 9 and 10 on governor control assembly. Shields should be grounded at governor control grounding stud. Individual shields should not have multiple ground connections. Magnetic pickup from governor control assembly is not needed. Use magnetic pickup from speed switch group. Wire from magnetic pickup to (DSS). Then wire from (DSS) to governor control assembly using to conductor shielded cable - terminal 4 on (DSS) to terminal 8 on governor control assembly, terminal 3 on (DSS) to terminal 7 on governor control assembly. Remove (MP) shield from terminal 2 on (DSS) and connect to shield on governor cable, ground the shield at the governor control assembly ground stud. The (DSS) may be installed physically near the governor control assembly if desired.

NOTE B: For load sharing operation - magnetic pickup (MP) and oil pressure contactor (OPS) must be wired to governor control with two conductor shielded cable (Beldon Mfg. Co. type 8780 or equivalent). (MP) should be connected to terminals 18 and 19 on governor control assembly and (OPS) should be connected to terminals 14 and 15 on governor control assembly. Shields should be grounded at governor control assembly grounding stud. Individual shields should not have multiple ground connections. Magnetic pickup (MP) from governor control assembly is not needed. Use (MP) from speed switch group. Wire from (MP) to (DSS). Then wire from (DSS) to governor control assembly using two conductor shielded cable - terminal 4 on (DSS) to terminal 19 on governor control assembly, terminal 3 on (DSS) to terminal 18 on governor control assembly. Remove (MP) shield from terminal 2 (DSS) and connect to shield on governor cable. Ground the shield at the governor control assembly grounding stud. The (DSS) may be installed physically near the governor control assembly if desired.

Automatic Start/Stop System Schematic

Electric Shutoff And Alarm Systems

Introduction

There are three types of electrical protection systems available for the 3406C Engines.

1. Water Temperature and Oil Pressure Protection.

2. Water Temperature, Oil Pressure and Overspeed Protection.

3. Automatic Start Stop Systems for Non-Package Generator Sets.

The electric shut-off system is designed to give protection to the engine if there is a problem or a failure in any of the different engine systems. The engine systems that are monitored are: engine overspeed, starting motor crank terminate, engine oil pressure and engine coolant temperature.

The electric protection system consists of the electronic speed switch and time delay relay. This system monitors the engine from starting through rated speed.

Dual Speed Switch (DSS)

The speed switch has controls (in a single unit) to monitor engine overspeed and crank terminate speed.

Engine Overspeed

An adjustable engine speed setting (normally 118 percent of rated speed) that gives protection to the engine from damage if the engine runs too fast. This condition will cause a switch to close that shuts off the fuel to the engine.

Crank Terminate (Starting Motor)

An adjustable engine speed setting that gives protection to the starting motor from damage by overspeed. This condition will cause a switch to open that stops current flow to starting motor circuit, and the starting motor pinion gear will then disengage from engine flywheel ring gear. The crank terminate can also be used to activate the time delay relay.

Time Delay Relay

This relay has special ON/OFF switches with two controls that will either make the relay activate immediately, or after a nine second delay. The time delay relay is used to arm the shutdown system. The time delay relay has a 70 second delay to be sure of complete engine shutdown.

Water Temperature Contactor Switch

This contactor switch is a separate unit that is wired into the shutdown circuit. It has an element that feels the temperature of the coolant (it must be in contact with the coolant). When the engine coolant temperature becomes too high, the switch closes to cause the fuel to be shut off to the engine. The switch is installed in the top front of the cylinder head.

Engine Oil Pressure Switch

This switch is installed in the main oil gallery on the right side of the cylinder block. The oil pressure switch is used to determine low engine oil pressure and to activate the time delay relay.

Wiring Diagrams

Abbreviations, wire codes and recommended wire sizes, used with the wiring diagrams that follow, can be found at the front of the Wiring Diagrams Section.

The notes that follow are used with the wiring diagrams shown in this section.

NOTE: Customer to Furnish Battery and All Wires Shown Dotted

NOTE A: Optional ground to engine may be used with grounded systems only.

NOTE B: These leads terminate at the starting motor and must be omitted when there is no starting motor. In this case customer must provide DC power at the other termination point of these two leads.

NOTE C: If 2301A Governor is used, only one magnetic pickup is required. Use magnetic pickup from overspeed group. Wire magnetic pickup to speed switch. Then wire from speed switch to the 2301A Governor. The speed switch may be installed physically near the 2301A if desired.

NOTE D: Electronic dual speed switch and electronic time delay relay can be wired to battery power continuously since the system will draw less than 40 MA current when the engine is not running.

NOTE E: If required, customer is to supply (RNS) Remote Normal Shutdown Switch. Requires a single pole N/O switch with a minimum contact rating of 5 amps inductive at the charging system voltage. Can be a latching switch if customer prefers. Shuts off engine fuel when activated.

NOTE F: If required, customer is to supply (RESS) Remote Emergency Shutdown Switch. Requires a single pole N/O switch with a minimum contact rating of 5 amps inductive at the charging system voltage. Can be latching switch if customer prefers. Shuts off engine air and fuel when activated. This shut-off mode must not be used for normal engine shutdown.

Water Temperature And Oil Pressure Shutoff System

With Time Delay Relay

Wiring Diagram (Fuel Shutoff Solenoid Energized to Shutoff)
(1) Time delay relay. (2) Oil pressure switch. (3) Water temperature switch. (4) Switch (N/O). (5) Circuit breaker. (6) Shutdown relay. (7) Battery. (8) Diode assembly. (9) Fuel shutoff solenoid. (10) Starting motor.

When the engine starts, engine oil pressure will close the N/O switch and open the N/C switch in oil pressure switch (2). This completes the circuit to time delay relay (1). Switch. (4) in the time delay relay now closes and completes the circuit between shutdown relay (6) and terminal TD-7 of the time delay relay.

If the engine coolant temperature goes above the setting of water temperature switch (3), the N/O contacts will close. This lets current flow through water temperature switch (3) and through switch (4) to activate shutdown relay (6) which in turn activates fuel shutoff solenoid (9). When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N/O switch will open and stop the flow of current to the time delay relay timer. After 70 seconds, switch (4) will open to stop current flow through shutdown relay (6). Now, fuel shutoff solenoid (9) will no longer be activated.

If engine oil pressure gets less than the setting of the oil pressure switch, the N/C switch will close. This will let current flow through switch (4) to activate shutdown relay (6) which in turn activates fuel shutoff solenoid (9). The N/O switch will open and start the time delay relay timer. After 70 seconds, switch (4) will open to stop current flow through shutdown relay (6). Now, fuel shutoff solenoid (9) will no longer be activated.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to shutdown before the engine is started again.

Water Temperature, Oil Pressure And Electronic Overspeed Shutoff System

With Time Delay Relay

Wiring Diagram (Fuel Shutoff Solenoid Energized To Shutoff)
(1) Magnetic pickup. (2) Dual speed switch. (3) Overspeed switch. (4) Crank terminate switch. (5) Water temperature switch. (6) Oil pressure switch. (7) Time delay relay. (8) Switch (N/O). (9) Shutdown relay. (10) Battery. (11) Diode assembly. (12) Fuel shutoff solenoid. (13) Starting motor.

The engine speed is felt by magnetic pickup (1). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (2) measures engine speed from the frequency of the voltage.

Time delay relay (7) controls the operation of shutdown relay (9), which in turn, controls the operation of fuel shutoff solenoid (12). Time delay relay (7) will keep the fuel shutoff solenoid energized for 70 seconds after a fault condition This prevents the engine from being started again before the flywheel has stopped rotation.

When the engine starts and gets to a speed just above cranking speed, the normally open contacts of crank terminate switch (4) [which is part of dual speed switch (2)] will close. This will complete the circuit to time delay relay (7) through terminal TD-2. In approximately 9 seconds switch (8) in time delay relay (7) will close and complete the circuit between shutdown relay (9) and terminal TD-7 of the time delay relay. If the engine oil pressure has not activated oil pressure switch (6) by 9 seconds, current will flow through the N/C switch in the oil pressure switch and through the now closed switch (8) to activate shutdown relay (9) which in turn activates fuel shutoff solenoid (12). If engine oil pressure activates oil pressure switch (6), the N/O switch will close and the N/C switch will open. This will let current flow to terminal TD-1 of the time delay relay and immediately close switch (8). At the same time the N/C switch in the oil pressure switch will open and prevent current flow to switch (8).

If the engine speed increases above the overspeed setting (118 percent of rated speed) of the dual speed switch, the overspeed switch (part of the dual speed switch) will close across terminals DSS-7 and DSS-8. This completes the circuit to shutdown relay (6) through the now closed switch (8) at terminal TD-7. Shutdown relay (9) is activated and in turn activates fuel shutoff solenoid (12) to cause the engine to shutdown.

When the engine speed gets less than the cranking speed setting, crank terminate switch (4) opens. This stops the flow of current to terminal TD-2 of the time delay relay. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N/O switch will open and stop the flow of current to terminal TD-1 of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (8) will open and stop current flow to shutdown relay (9) and fuel shutoff solenoid (12) will no loner be activated.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed before the engine is started again.

After an overspeed shutdown, a button on the dual speed switch must be pushed to open the overspeed switch before the engine will run.

When the engine has been started and is running, the time delay relay will close switch (8). If the engine coolant temperature goes above the setting of water temperature switch (5), the N/O contacts will close. This lets current flow through the water temperature switch and through switch (8) to activate shutdown relay (9) and in turn activates fuel shutoff solenoid (12).

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to get too hot before the engine is started again.

When the engine has been started and is running, the time delay relay will close switch (8). If the engine oil pressure gets less than the setting of oil pressure switch (6), the N/C switch will close. This will let current flow through switch (8) to activate shutdown relay (9) and in turn activates fuel shutoff solenoid (12). The N/O switch will also open and stop current flow to terminal TD-1 of the time delay relay. When the engine speed gets less than the cranking speed setting, crank terminate switch (4) opens. This stops the flow of current to terminal TD-2 of the time delay relay and starts the time delay relay timer. After 70 seconds, switch (8) will open and stop current flow to shutdown relay (9) and fuel shutoff solenoid (12) will no longer be activated.

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NOTICE

To help prevent damage to the engine, find and correct the cause for low engine oil pressure before the engine is started again.

Water Temperature, Oil Pressure And Electronic Overspeed With Air Shutoff

With Time Delay Relay

Wiring Diagram (Fuel Shutoff Solenoid Energized to Shutoff)
(1) Magnetic pickup. (2) Dual speed switch. (3) Overspeed switch. (4) Crank terminate switch. (5) Water temperature switch. (6) Oil pressure switch. (7) Time delay relay. (8) Switch (N/O). (9) Fuel shutdown relay. (10) Diode. (11) Air shutdown relay. (12) Fuel shutoff solenoid. (13) Air shutoff solenoid. (14) Starting motor. (15) Battery.

This system gives high water temperature, low oil pressure and overspeed protection. The air inlet shutoff system is used with fuel shutoff system to give overspeed protection to the engine and is activated only by an overspeed condition. The air inlet shutoff system consists of diode (10), shutdown relay (11), air shutoff solenoid (13) and a shutoff valve. The location of the shutoff valve and shutoff solenoid is in the air inlet pipe to the engine.

When an engine has an overspeed condition the air shutdown relay (11) is activated by the same signal from time delay relay (7) that activates fuel shutdown relay (9).

NOTE: See Water Temperature, Oil Pressure And Electronic Overspeed Shutoff System for more details of the systems operation.

After an overspeed condition, a reset button on the dual speed switch must be pushed to open the overspeed switch and the air inlet shutoff valves must be manually reset before the engine will run.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to shutdown, before the engine is started again.

Diode (10) keeps the air shutoff solenoid circuit separate from the fuel shutoff circuit. This lets a manual shutdown switch be connected to fuel shutdown relay (9) and does not activate air shutdown relay (11) when the switch is closed to manually shutdown the engine.

Electronic Overspeed Shutoff System

With Time Delay Relay

Wiring Diagram (Fuel Shutoff Solenoid Energized To Shutoff)
(1) Magnetic pickup. (2) Crank terminate switch. (3) Dual speed switch. (4) Time delay relay. (5) Switch (N/O). (6) Shutdown relay. (7) Battery. (8) Diode assembly. (9) Fuel shutoff solenoid. (10) Starting motor.

The engine speed is felt by magnetic pickup (1). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (3) measures engine speed from the frequency of this AC voltage.

Time delay relay (4) controls the operation of shutdown relay (6), which in turn, controls the operation of fuel shutoff solenoid (9). Time delay relay (4) will keep the fuel shutoff solenoid energized for 70 seconds after a fault condition. This prevents the engine from being started again before the flywheel has stopped rotation.

When the engine starts and gets to a speed just above cranking speed, the normally open contacts of crank terminate switch (2) [which is part of dual speed switch (3)] will close. This will complete the circuit to time delay relay (4) through terminal TD-1. Normally open switch (5) in time delay relay (4) now closes and completes the circuit between shutdown relay (6) and terminal TD-7.

If the engine speed increases above the overspeed setting (118 percent of rated speed) of the dual speed switch, the overspeed switch (part of the dual speed switch) will close across terminals DSS-7 and DSS-8. This completes the circuit to shutdown relay (6) through the now closed switch (5) at terminal TD-7. Shutdown relay (6) is activated and in turn activates fuel shutoff solenoid (9) to cause the engine to shutdown.

When the engine stops, crank terminate switch (2) will open the circuit across terminals DSS-10 and DSS-11. This stops current flow to time delay relay (4). Now, the time delay relay timer is started and 70 seconds later, switch (5) will open the circuit at terminal TD-7. Current flow is then stopped through shutdown relay (6) and fuel shutoff solenoid (9) will no longer be activated.

A reset button on the dual speed switch must be pushed to open the overspeed switch before the engine will run.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed, before the engine is started again.

Electronic Overspeed With Air Shutoff

With Time Delay Relay

Wiring Diagram (Fuel Shutoff Solenoid Energized to Shutoff)
(1) Magnetic pickup. (2) Crank terminate switch. (3) Dual speed switch. (4) Time delay relay. (5) Switch (N/O). (6) Fuel shutdown relay. (7) Diode. (8) Air shutdown relay. (9) Fuel shutoff solenoid. (10) Air shutoff solenoid. (11) Starting motor. (12) Battery.

The air inlet shutoff system is used with the fuel shutoff system to give overspeed protection to the engine. The air inlet shutoff system consists of diode (7), air shutdown relay (8), air shutoff solenoid (10) and a shutoff valve. The location of the shutoff valve and shutoff solenoid is in the air inlet pipe to the engine.

When an engine has an overspeed condition, the air shutdown relay (8) is activated by the same signal from time delay relay (4) that activates fuel shutdown relay (6). See Electronic Overspeed Shutoff System for details of the system operation.

After an overspeed condition, a reset button on the dual speed switch must be pushed to open the overspeed switch and the air inlet shutoff valves must be manually reset before the engine will run.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed, before the engine is started again.

Diode (7) keeps the air shutoff solenoid circuit separate from the fuel shutoff solenoid circuit. This lets a manual switch be connected to fuel shutdown relay (6) and does not activate air shutdown relay (8) when the switch is closed to manually shutdown the engine.

Alarm Contactor System

Wiring Diagram
(1) Oil pressure switch. (2) Water temperature contactor. (3) Source voltage. (4) Toggle switch (optional). (5) Alarm. (6) Signal lights.

If the oil pressure is too low or the water temperature is too high this system will activate alarm (5) and signal lights (6).

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NOTICE

When the alarm and signal lights activate, stop the engine immediately. This will help prevent damage to the engine from heat or not enough lubrication. Find and correct the problem that caused the alarm and signal lights to activate.

Before the engine is started it will be necessary to override oil pressure switch (1) or the alarm will activate. This is done by either a manual override button on the (earlier) oil pressure switch or toggle switch (4). Oil pressure will return the manual override button to the run position. The toggle switch must be manually closed when the engine has oil pressure.

Wiring Diagram
(1) Oil pressure switch. (2) Water temperature contactor. (3) Source voltage. (4) Toggle switch (optional). (6) Signal lights (three). (7) Air temperature contactor.

If the oil pressure is too low or the water temperature is too high this system will activate signal lights (6).

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NOTICE

When the signal lights activate, stop the engine immediately. This will prevent damage to the engine from heat or not enough lubrication. Find and correct the problem that caused the signal lights to activate.

Before the engine is started it will be necessary to override oil pressure switch (1) or the signal lights will activate. This is done by either a manual override button on the (earlier) oil pressure switch or toggle switch (4). Oil pressure will return the manual override button to the run position. The toggle switch must be manually closed when the engine has oil pressure.

Wiring Diagram
(1) Oil pressure switch. (2) Water temperature contactor. (3) Source voltage. (4) Toggle switch (optional). (5) Alarm. (7) Air temperature contactor.

If the oil pressure is too low or the water temperature is too high this system will activate alarm (5).

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NOTICE

When the alarm activates, stop the engine immediately. This will help prevent damage to the engine from heat or not enough lubrication. Find and correct the problem that caused the alarm to activate.

Water Temperature And Oil Pressure Shutoff System

With Oil Pressure Delay Or Fuel Pressure Switch

Wiring Diagram
(1) Oil pressure switch. (2) Water temperature contactor. (3) Oil pressure (time delay) or fuel switch. (4) Rack solenoid. (5) Diode assembly. (6) Starter. (7) Battery.

If the oil pressure is too low or the coolant temperature is too high this system will activate rack solenoid (4). The solenoid is connected to the fuel rack by linkage. When it is activated it will move to stop the flow of fuel to the engine. The engine will stop.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to shutdown before the engine is started again.

Before the engine can be started it will be necessary to push the manual override button on (earlier) oil pressure switch (1). Oil pressure will return the manual override button to the run position.

Diode assembly (5) is used to stop arcing, for protection of the system.

Oil pressure (time delay) or fuel switch (3) is used to prevent discharge of battery (7) through the solenoid when the engine is stopped.

Electronic Overspeed Shutoff System

With Oil Pressure Delay Or Fuel Pressure Switch

Wiring Diagram
(1) Rack Solenoid. (2) Oil pressure (time delay) or fuel pressure switch. (3) Dual speed switch. (4) Magnetic pickup. (5) Diode assembly. (6) Starter. (7) Battery.

The engine speed is felt by magnetic pickup (4). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (3) measures engine speed from the frequency of this AC voltage.

Rack solenoid (1) is connected to the fuel rack by linkage. When it is activated, it will move to stop the flow of fuel to the engine.

If the engine speed increases above the overspeed setting (118 percent of rated speed) of the dual speed switch, the overspeed switch [which is part of dual speed switch (3)] will close across terminals DSS-7 and DSS-8. This completes the circuit to rack solenoid (1) through the now closed oil pressure (time delay) or fuel pressure switch (2) and activates the solenoid to shutdown the engine.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed, before the engine is started again.

After an overspeed shutdown, a button on the dual speed switch must be pushed to open the overspeed switch before the engine will run.

Diode assembly (5) is used to stop arcing, for protection of the system.

An oil pressure (time delay) or fuel pressure switch (2) is used to prevent discharge of battery (7) through the solenoid when the engine is stopped. The dual speed switch can be connected to the battery constantly because it uses less than 20 MA of current when the engine is stopped.

Electronic Overspeed With Air Shutoff

With Oil Pressure Delay Or Fuel Pressure Switch

Wiring Diagram
(1) Rack solenoid. (2) Oil pressure (time delay) or fuel pressure switch. (3) Dual speed switch. (4) Magnetic pickup. (5) Diode assembly. (6) Diode. (7) Air shutoff solenoids. (8) Starting motor. (9) Battery.

This system gives overspeed protection. Air shutoff solenoids (7) control a valve assembly in the air inlet pipe. When the solenoids are activated, the valve closes to shut off air to the engine. When the engine has an overspeed condition, the air shutoff solenoids are activated by the same signal from the overspeed switch [part of dual speed switch (3)] that activates rack solenoid (1). See Electronic Overspeed Shutoff System for more detail of the system operation.

Diode assembly (5) is used to stop arcing, for protection of the system.

Diode (6) keeps the air shutoff solenoid circuit separate from the rack solenoid circuit. For example, if a manual switch was connected to the rack solenoid, the air shutoff solenoids would not activate when the switch was closed.

After an overspeed condition, a reset button on the dual speed switch must be pushed to open the overspeed switch and the air inlet shutoff valves must be manually reset before the engine will run.

Water Temperature, Oil Pressure And Electronic Overspeed Shutoff System

With Oil Pressure Delay Or Fuel Pressure Switch

Wiring Diagram
(1) Oil pressure switch. (2) Oil pressure (time delay) or fuel pressure switch. (3) Water temperature contactor. (4) Dual speed switch. (5) Magnetic pickup. (6) Rack solenoid. (7) Diode assembly. (8) Starting motor. (9) Battery.

This system gives high water temperature, low oil pressure and overspeed protection to the engine.

Rack solenoid (6) is connected to the fuel rack by linkage. When it is activated it will move to stop the flow of fuel to the engine. The rack solenoid can be activated by oil pressure switch (1), water temperature contactor (3) or the overspeed switch that is part of dual speed switch (4).

If the oil pressure is too low or the coolant temperature is too high, oil pressure switch (1) or water temperature contactor (3) will close to complete the circuit and activate rack solenoid (6).

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to shutdown before the engine is started again.

The engine speed is felt by magnetic pickup (5). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (4) measures engine speed from the frequency of this AC voltage.

If the engine speed increases above the overspeed setting (118 percent of rated speed) of the dual speed switch, the overspeed switch [which is part of dual speed switch (4)] will close across terminals DSS-7 and DSS-8. This completes the circuit rack solenoid (6) through oil pressure (time delay) or fuel pressure switch (2) and water temperature contactor (3) to activate the solenoid and shutdown the engine.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed, before the engine is started again.

After an overspeed shutdown, a button on the dual speed switch must be pushed to open the overspeed switch before the engine will run.

Diode assembly (7) is used to stop arcing, for protection of the system.

An oil pressure (time delay) or fuel pressure switch (2) is used to prevent discharge of battery (9) through the solenoid when the engine is stopped. The dual speed switch can be connected to the battery constantly because it uses less than 20 MA current when the engine is stopped.

Water Temperature, Oil Pressure And Electronic Overspeed With Air Shutoff

With Oil Pressure Delay Or Fuel Pressure Switch

This system gives high water temperature, low oil pressure and overspeed protection. The air inlet shutoff system is used with the fuel shutoff system to give overspeed protection to the engine and is activated only by an overspeed condition. The air inlet shutoff system consist of diode (8), air shutoff solenoid (9) and a shutoff valve. The location of the shutoff valve and shutoff solenoid is in the air inlet pipe to the engine. Engines with two turbochargers have two shutoff valves and solenoids.

When an engine has an overspeed condition air shutoff solenoid (9) is activated by the same signal from the overspeed switch [which is part of dual speed switch (4)] that activates rack solenoid (6).

NOTE: See Water Temperature, Oil Pressure And Electronic Overspeed Shutoff System for more details of the systems operation.

After an overspeed condition, a reset button on the dual speed switch must be pushed to open the overspeed switch and the air inlet shutoff valves must be manually reset before the engine will run.

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NOTICE

To help prevent damage to the engine, find and correct the problem that caused the engine to shutdown, before the engine is started again.

Diode (8) keeps the air shutoff solenoid circuit separate from the fuel shutoff circuit. This lets a manual shutdown switch be connected to rack solenoid (6) and does not activate air shutoff solenoid (9) when the switch is closed to manually shutdown the engine.

NOTE: On systems that use an earlier type oil pressure switch, it will be necessary to push the manual override button before the engine can be started. Oil pressure will return the manual override button to the run position.

Mechanical Shutoff And Alarm Systems

Mechanical Oil Pressure And Water Temperature Shutoff

Mechanical Oil Pressure And Water Temperature Shutoff (Typical Example)
(1) Outlet line. (2) Inlet line. (3) Drain line. (4) Shut down cylinder knob. (5) Water temperature control valve. (6) Shut down cylinder oil inlet port. (7) Oil pressure shut down cylinder. (8) Oil pressure control valve.

System Schematic

Oil pressure shut down cylinder (7) is fastened to the governor. Before the engine is started the shut down cylinder knob (4) is used to pull a piston away from the fuel rack and compresses a pressure spring. With the shut down cylinder knob (4) held in this position the engine can be started.

When the engine starts, oil pressure will build in the oil pressure control valve (8). When oil pressure is high enough, pressure oil will flow from the oil pressure control valve (8) through the shut down cylinder oil inlet port (6) into the space between the piston and the housing. As long as the engine has enough oil pressure the fuel rack will be controlled by the governor.

If the engine oil pressure gets too low the oil pressure control valve (8) will divert pressure oil back to the crankcase. This will create a loss of oil pressure in the oil pressure shut down cylinder. The force of the compression in the spring will over come the oil pressure and move the piston against the fuel rack. This will move the rack to stop the flow of fuel to the engine. The engine will stop.

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NOTICE

Find and correct the problem that caused the engine to stop. This will help prevent damage to the engine from not enough lubrication.

Temperature Shutoff Control Valve
(9) Inlet port. (10) Outlet port. (11) Thermostat assembly. (12) Drain port.

Water temperature control valve (5) is a control valve for the oil pressure shutoff. When the water temperature becomes too high the thermostat assembly (11) causes an internal valve to move. Pressure oil at inlet port (9) will then be diverted inside the valve from the outlet port (10) to the drain port (12)). The diverted pressure oil will flow out the drain port (12) into the engine crankcase. This will cause the oil pressure to decrease. The oil pressure control valve (8) will sense this and divert oil from the oil pressure shut down cylinder (7) to the crankcase causing a loss of pressure oil in the shut down cylinder (7). This will move the rack to stop the flow of fuel to the engine. The engine will stop.

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NOTICE

Find and correct the problem that caused the engine to stop. This will help prevent damage to the engine from too much heat.

Shutoff And Alarm System Components

Oil Pressure Switch

Micro Switch Type

Oil Pressure Switch (Micro Switch Type)
(1) Locknut. (2) Adjustment screw. (3) Spring. (4) Arm. (5) Spring. (6) Bellows. (7) Latch plate. (8) Button (for micro switch). (9) Arm. (10) Projection (of arm).

The oil pressure switch is used to give protection to the engine from damage because of low pressure. When oil pressure lowers to the pressure specifications of the switch, the switch closes and activates the rack shutoff solenoid.

On automatic start/stop installations, this switch closes to remove the starting system from the circuit when the engine is running with normal oil pressure.

This switch for oil pressure can be connected in a warning system for indication of low oil pressure with a light or horn.

As pressure of the oil in bellows (6) becomes higher, arm (4) is moved against the force of spring (3). When projection (10) of arm (4) makes contact with arm (9), pressure in the bellows moves both arms. This also moves button (8) of the micro switch to activate the micro switch.

Some of these switches have a "Set For Start" button. When the button is pushed in, the micro switch is in the START position. This is done because latch plate (7) holds arm (9) against button (8) of the micro switch and the switch operates as if the oil pressure was normal. When the engine is started, pressure oil flows into bellows (6). The bellows move arm (4) into contact with latch plate (7). The latch plate releases the "Set For Start" button and spring (5) moves it to the RUN position. This puts the switch in a ready to operate condition.

Pressure Switch

Pressure switches are used for several purposes and are available with different specifications. They are used in the oil system and in the fuel system. One use of the switch is to open the circuit between the battery and the rack shutoff solenoid after the oil pressure is below the pressure specifications of the switch. It also closes when the engine starts.

Another use of the switch is to close and activate the battery charging circuit when the pressure is above the pressure specification of the switch. It also disconnects the circuit when the engine is stopped.

Switches of this type have three terminal connections. They are used to do two operations with one switch. They open one circuit and close another with the single switch.

Shutoff Solenoid

Rack Shutoff Solenoid (Typical Example)

A shutoff solenoid changes electrical input into mechanical output. It is used to move the fuel injection pump rack to the off position. It can also be used to move a valve assembly in the air inlet pipe to a closed position. This stops the engine.

The shutoff solenoid can be activated by any one of the many sources. The most usual are: water temperature contactor, oil pressure switch, overspeed switch and remote manual control switch.

Water Temperature Contactor Switch

The contactor switch for water temperature is installed in the water manifold. No adjustment to the temperature range of the contactor can be made. The element feels the temperature of the coolant and then operates the micro switch in the contact when the coolant temperature is too high, the element must be in contact with the coolant to operate correctly. If the cause for the engine being too hot is because of low coolant level or no coolant, the contactor switch will not operate.

The contactor switch is connected to the rack shutoff solenoid to stop the engine. The switch can also be connected to an alarm system. When the temperature of the coolant lowers to the operating range, the contactor switch opens automatically.

Circuit Breaker

Circuit Breaker Schematic
(1) Disc in open position. (2) Contacts. (3) Disc. (4) Circuit terminals.

The circuit breaker gives protection to an electrical circuit. Circuit breakers are rated as to how much current they will permit to flow. If the current in a circuit gets too high it will cause heat in disc (3). Heat will cause distortion of the disc and contacts (2) will open. No current will flow in the circuit.

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NOTICE

Find and correct the problem that caused the circuit breaker to open. This will help prevent damage to the circuit components from too much current.

An open circuit breaker will close (reset) automatically when it becomes cooler.

Electronic Speed Switch

Electronic Speed Switch
(1) Reset button. (2) Lamp.

The electronic speed switch (dual speed switch) activates the shutoff solenoid when the engine speed gets approximately 18 percent higher than the rated full load speed of the engine. It also stops current flow to the starting motor after the engine starts.

The electronic speed switch makes a comparison between the output frequency of the magnetic pickup and the setting of the electronic speed switch. When they are equal, the normally open contacts in the electronic speed switch close. Lamp (2) will go on. The switch also has a failsafe circuit that will cause the engine to shutdown if there is an open in the magnetic pickup circuit.

When the engine is stopped, it will be necessary to push reset button (1), before the engine can be started.

Cooling System

Coolant Conditioner

Cooling System With Coolant Conditioner
(1) Cylinder liner. (2) Coolant bypass line. (3) Coolant outlet (to radiator). (4) Radiator. (5) Temperature regulator. (6) Water pump. (7) Coolant conditioner element. (8) Engine oil cooler. (9) Coolant inlet (from radiator).

Some conditions of operation have been found to cause pitting (small holes in the metal surface) from corrosion or cavitation erosion (wear caused by air bubbles in the coolant) on the outer surface of the cylinder liners and the inner surface of the cylinder block next to the liners. The addition of a corrosion inhibitor (a chemical that gives a reduction of pitting) can keep this type of damage to a minimum.

The "spin-on" coolant condition elements, similar to the fuel filter and oil filter elements, fasten to a base that is mounted on the engine or is remote mounted. Coolant flows through lines from the water pump to the base and back to the block. There is a constant flow of coolant through the element.

The element has a specific amount of inhibitor for acceptable cooling system protection. As coolant flows through the element, the corrosion inhibitor, which is dry material, dissolves (goes into solution) and mixes to the correct concentration. Two basic types of elements are used for the cooling system, and they are called the "Precharge" and the "Maintenance" e elements. Each type of element has a specific use and must be used correctly to get the necessary concentration for cooling system protection. The elements also contain a filter and should be left in the system so coolant flows through it after the conditioner material is dissolved.

The "Precharge" element has more than the normal amount of inhibitor, and is used when a system is first filled with new coolant. This element has to add enough inhibitor to bring the complete cooling system up to the correct concentration.

The "Maintenance" elements have a normal amount of inhibitor and are installed at the first change interval and provide enough inhibitor to keep the corrosion protection at an acceptable level. After the first change period, only "Maintenance" elements are installed at specified intervals to give protection to the cooling system.

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NOTICE

Do not use any Methoxy Propanol/Based Antifreezes or coolant in the Cooling System. Do not use Dowtherm 209 Full-Fill in a cooling system that has a coolant conditioner. These two systems are not compatible (corrosion inhibitor is reduced) when used together.