Introduction

The forward acting KG30 Governor Control Unit provides the electrical actuator with increased electrical signals as more fuel is needed by the engine. This type of control will cause the actuator to go to minimum fuel position if the electrical signal is lost.

The LMG 03 Loadshare Unit is used when paralleling with other generators. It measures the output of the generator and compares its output with other generators on the same bus thru paralleling lines. It then sends a corrective signal to the KG30 Control Unit. The control unit sends a corrective signal to the StG30 actuator to increase or decrease fuel to share the load accurately between the engines. The LMG 03 is also used effectively when paralleling the generator to the utility.

Since the E30 system uses an all electric actuator, it eliminates the need for a mechanical governor drive and actuator oil supply. All static settings (idle speed, rated speed, percent droop) can be performed to a high degree of accuracy and confidence before the engine is started.

E30 Electric Governor System

The E30 Electric Governor Control System consists of the components that follow: KG30 Governor Control Unit, StG30 Actuator, Magnetic Pickup, Remote Speed Set Point Potentiometer and usually the LMG 03 Loadshare Unit.

KG30 Governor Control Unit

The E30 Electric Governor System gives precision engine speed control. The KG30 Governor Control Unit measures engine speed constantly and makes necessary corrections to the engine fuel setting through the StG30 actuator connected to the fuel system.

The engine speed is sensed by a magnetic pickup. The pickup generates an AC voltage that is sent to the KG30 Governor Control Unit. The KG30 Governor Control Unit then sends a pulsed DC voltage signal to the actuator.

StG30 Actuator (With Base)
(1) Position indicator plate. (2) Connector (from governor control unit). (3) Actuator output shaft. (4) Position indicator.

StG30 Actuator (Without Base)
(1) Position indicator plate. (2) Connector (from governor control unit). (3) Actuator output shaft. (4) Position indicator.

The StG30 actuator changes the electrical input from the KG30 Governor Control Unit to a mechanical output that is connected to the fuel system by linkage. For example, if the engine speed is greater than the speed setting, the KG30 Governor Control Unit will decrease its output and the StG30 actuator will move the linkage to decrease fuel to the engine.

The speed of the engine is adjusted between idle and rated with the remote speed set point potentiometer.

The LMG 03 Loadshare Unit, which is used when paralleling with other generators, measures the power output of the generator and compares its output with other generators on the same bus through paralleling lines. It then sends corrective signals to the KG30 Control Unit. The control unit in turn sends a corrective signal to the actuator to increase or decrease fuel to share the load accurately between the engines.

Basic System Schematic
(5) StG30 Actuator. (6) Engine. (7) Feedback line. (8) Magnetic pickup. (9) Fuse. (10) KG30 governor control unit. (11) Remote speed set point potentiometer. (13) Generator. (15) Bus.

Basic System Schematic For Kilowatt Load Sharing
(5) StG30 Actuator. (6) Engine. (7) Feedback line. (8) Magnetic pickup. (9) Fuse. (10) KG30 Governor Control Unit. (11) Remote speed set point potentiometer. (12) LMG 03 Loadshare Unit. (13) Generator. (14) Paralleling lines. (15) Bus.

KG30 Governor Control Unit

KG30 Governor Control Unit
(1) Diode. (2) Max fuel 5V potentiometer. (3) Stop 1.5V potentiometer. (4) Min speed potentiometer. (5) Max speed potentiometer. (6) Gain potentiometer. (7) Stability potentiometer. (8) Derivative potentiometer. (9) Gas-Gain potentiometer. (10) Gas-Diesel switch. (11) Start fuel limit potentiometer. (12) Start fuel limit slide switch. (13) Green LED light. (14) OV (-). (15) TP6 (+). (16) Droop potentiometer. (17) Droop-Isoch switch. (18) Speed variance potentiometer. (19) Fast response potentiometer. (20) Damping potentiometer.

KG30 Governor Control Unit
Earlier (Green Control Board)

KG30 Governor Control Unit
Later (White Control Board)

The KG30 Governor Control Unit provides precision engine speed control. The system measures engine speed constantly, and makes necessary corrections to the engine fuel setting through an actuator connected to the fuel system.

The engine speed is sensed by a magnetic pickup. As the teeth of the flywheel ring gear cuts through the magnetic lines of force around the pickup, an AC voltage is generated. The frequency of this voltage is directly proportional to engine speed. An electric circuit inside the governor control unit processes this AC voltage. In response it sends a signal from the control to the actuator to maintain the set speed.

The actuator is connected to the fuel system by linkage. It changes the electrical input from the governor control unit to mechanical output that changes the engine fuel setting. For example, if the engine speed was greater than the speed setting, the governor control unit will decrease fuel to the engine.

The Rated and Low Idle engine speeds are set with internal speed setting potentiometers. The engine speed is adjusted with a remote 10 turn potentiometer, or as a function of voltage, current or air pressure with an optional speed set point unit.

The Gain, Stability and Derivative Potentiometers control the speed stability and the response time of the engine to a change in load. Gain affects the amount of speed deviation and recovery time. Stability affects rate of recovery, overshoot and response time for the Gain setting used. Derivative affects rate of speed deviation and thus response time to some degree, but is mainly for additional fine-tuning of engine stability.

The Speed Droop Potentiometer controls the amount of speed droop. It can be set between 0 and 10%. Droop is only necessary when paralleling with a utility bus or a generator with a hydramechanical governor.

NOTE: When operating a generator set in droop where the LMG 03 Loadshare Unit is used, the KG30 Control Unit is put in Isochronous mode and the droop is set in the separate LMG 03 Loadshare Unit.

The Start Fuel Limit Potentiometer is used to control the amount of fuel to the engine during startup. It can be adjusted to make the engine start easier, to decrease startup smoke and to limit startup overshoot. The fuel limiting function is turned off automatically when the speed control takes over.

The speed failsafe circuit will drive the actuator to shutoff if the magnetic pickup signal becomes less than 150 Hz. Magnetic pickup failure or slow engine cranking will cause the actuator to move to the FUEL OFF position. The engine will not start if the magnetic pickup signal has a failure.

STG30 Actuator

StG30 Actuator
(1) Output shaft. (2) Feedback probe. (3) Feedback cam. (4) DC disc motor. (5) Gearbox.

Actuator torque is generated by a DC disc armature motor (4) and transmitted to the actuator output shaft (1) by way of a gearbox (5).

A feedback cam (3) is mounted on the actuator output shaft (1) which is scanned without contact by a probe (2), with the result that the precise position of the output shaft (1) is transmitted to the governor control unit.

If the actuator is driven against a rack stop, the current limitation will take effect after approximately 20 seconds. It will reduce the current to the actuator to a value that cannot harm the motor.

This type actuator provides the following advantages:

1. High regulating power working in both directions.

2. Extremely low current consumption during steady state and relatively low current consumption on change of load.

3. Indifference to slow voltage changes in the supply.

Basic Mechanical System

The engine fuel rack linkage is connected to the actuator terminal shaft. When there is an increase or decrease in engine load, the movement of the actuator motor will turn the terminal shaft. The linkage will now move the fuel racks to the new fuel setting to maintain the correct engine speed at the new load condition.

Basic Electrical System

A magnetic pickup is installed in the flywheel housing to generate an AC voltage signal. The frequency of this AC signal is controlled by the speed of the gear teeth that cut through the magnetic field of the pickup. This engine speed frequency signal is sent to the Electric Governor Control Unit. The KG30 Governor Control Unit has a speed sensor that now makes a comparison between this input signal for actual engine speed and the desired engine speed that the governor control unit has been set to maintain. If the actual engine speed and the speed setting are not the same, the KG30 Governor Control Unit will send a corrective signal to the motor of the actuator. The actuator will now adjust to a new fuel setting to make the engine speed the same as the speed setting.

Feedback System

A high degree of stability is necessary to maintain a constant output from the engine. The stability of a system controlled by the KG30 Governor Control Unit is increased with the use of an actuator feedback signal that biases (makes a correction to) the KG30 Governor Control Unit command signal to the actuator. Since the KG30 Governor Control Unit makes an adjustment rapidly to a change in engine load, the actuator can make the engine go into a "hunt" condition (temporary increase and decrease in engine speed) if the correction are too sensitive. The purpose of the feedback system is to prevent over-correction to the load change. The feedback voltage can be measured at two terminals inside the KG30 using a DC voltmeter. This is an aid for setting up and troubleshooting the governor system.

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 KG30 Governor Control Unit where a conversion is made to DC voltage. The KG30 Governor Control Unit compares this actual speed signal to the set point speed signal and corrects any speed error with a signal to the actuator.

Remote Speed Set Point Potentiometer

Potentiometer

A 10-turn, 5000 ohm rotary potentiometer is used to remotely adjust the engine speed between the minimum and maximum speed preset in the KG30 Governor Control Unit. A second potentiometer is usually used with the LMG 03 Loadshare Unit to set and adjust the generator output when paralleled with the utility, or optionally to remotely set the load limit in the LMG 03 Loadshare Unit.

LMG 03 Loadshare Unit

LMG 03 Loadshare Unit

The LMG 03 Loadshare Unit provides isochronous kilowatt load sharing between two or more generator sets, regardless of size. The output of each generator in the system is constantly measured by its LMG 03 Loadshare Unit. Generator outputs are compared between load sharing units through paralleling wires between all of the generators on the same bus. From the inputs of the paralleling wires, the load sharing units send corrective signals to their respective KG30 controls. The controls in turn send corrective signals to the actuators. This gives kilowatt load sharing in proportion to generator ratings.

The following functions can be performed with the LMG 03:

(1) Isochronous load sharing.

(2) Droop load sharing.

(3) Kilowatt load limiting.

In addition, the loadshare unit has the following features:

(1) Reverse power relay with LED and choice between 5% or 10% reverse power limit on all 3 phases.

(2) LED's indicating correct current transformer connection (all 3 phases).

The three adjustments on the LMG 03 Loadshare Unit are droop, load limiting and load gain. Droop can be adjusted between the isochronous and 10%. Load limiting adjusts the kilowatt output limit of the generator from 50 to 100%. Load gain is set the same for all generators on the same bus (generally to 6 volts at full load).

Additional accessories, such as load anticipation unit, synchronizer, load switching unit and others can also be used with the E30 Control System.