Procedure A: Linkage Calibration

1. Verify that the levers on actuator and fuel control linkage are the correct length.

2. Inspect the rod ends. Rod end replacement should be made when side to side movement of ball (due to wear) will let ball face become flush with body sides.

ROD END

3. Install levers to actuator and fuel linkage at the correct angle. Fuel linkage must not bind at any position in travel range.

4. Make adjustment of linkage to fit levers. Verify that linkage will now move to shutoff and maximum fuel positions.

5. Run the engine at the highest notch position with the generator unloaded and measure the actuator amperage. All vertically mounted actuators should have 50 ma under no load conditions; all horizontally mounted actuators have 81 ma under no load conditions (except 3500 Engines). The 3500 Engine horizontally mounted actuator should have 50 ma under no load conditions. Make an adjustment of the linkage from the actuator to the fuel system to get this operating position. Make linkage connecting rod longer or shorter by 1/2 turn adjustments until correct actuator amperage is available. Actuators that can not operate at the amperage specified may not permit maximum fuel position for highly rated engines. These actuators should be returned to the factory for recalibration.

NOTE: See Service Manual for a specific engine or see Special Instruction SMHS7188 for the correct linkage geometry (lengths and angles).

Procedure B: Actuator Check Procedure

Installation

When actuator is mounted on the engine, be sure that correct alignment is made with the engine fuel linkage.

A gasket should be placed between the actuator and the base mounting pad. For vertically mounted actuators, be careful to not block the drain hole(s) next to the centering pilot of the base (see Figures 1 and 2). The oil that drains through drive shaft bore must flow freely to the sump. The splined drive shaft must fit into the drive with a free, slip fit; no tightness is permitted. The vertically mounted actuator must drop onto the mounting pad of its own weight without applying force.

The actuator gets its oil supply from a sump in the mounting base. The engine overflows the sump (from the engine lube circuit) through an orifice that meters flow. The sump can be checked for fill level with the actuator removed. Cranking the engine will not make any oil flow at the actuator oil supply port. The actuator base gasket must not permit air leakage into the supply port.

The engine fuel linkage must be free of binding and without backlash. If there is a collapsible member (permits compression) on the linkage, be sure the spring does not yield each time the actuator moves the linkage rapidly.

Fig. 1 EG-10P ACTUATOR

Actuator Troubleshooting

1. The Locomotive Governor Control must produce voltage at the lead terminals for actuator during engine cranking and operation. This voltage should be more than 4 volts during cranking. If correct voltage is present and actuator shaft does not have movement, stop the engine and disconnect actuator leads. Check the resistance leads. It should be between 30 and 40 ohms.

Disconnect the wiring connector from the actuator.

a. Put a jumper across pins C and D (on actuator). Measure the actuator coil resistance across pins A and B. It should be between 30 and 40 ohms. High resistance or an open circuit is an indication of a bad actuator.

Fig. 2 RESISTANCE MEASUREMENT OF ACTUATOR COIL

b. Inspect the wiring harness for damage. Check the fit of actuator pin to mating connector for a positive connection. Loose or corroded connectors should be repaired or replacement made.

2. Connect the actuator leads again. Disconnect fuel linkage from the actuator lever. Operate linkage manually to feel for binding or too much effort (force). Repair any linkage binding. If effort seems too high, measure force requirement of linkage for reference to actuator work effort (see Actuator Specifications for work effort available). If linkage effort is more than actuator specification, repair the linkage. If linkage effort is acceptable, install the linkage back to actuator lever. Remove pressure tap plug from actuator and install 6V2044 Pressure Gauge (See Figure 3). Crank the engine and read the oil pressure (see chart Electric Governor Actuator Specifications).

Fig. 3 EG-10P ACTUATOR (1/4 NPTF Pressure Tap)

a. If actuator fails to produce any effort in the FUEL ON direction, or there is no oil pressure, remove the actuator. Crank engine to see if there is drive rotation. Repair engine if drive does not rotate. Inspect drive spline connection for wear or shearing. Replace as necessary. Inspect actuator sump in engine for fill level. If level is low, clear plugged oil fill orifice in engine. Verify oil flow into sump during engine cranking.

b. If actuator oil pressure is low or pulses, inspect actuator base for any indication of air leakage into oil supply port, such as oil leakage at base gasket. Remove the actuator, inspect gasket mounting faces for burrs or debris which may prevent correct sealing of gasket interface. Crank the engine, inspect engine actuator sump for constant fill. Clear oil supply to sump if oil flow needs improvement.

c. Install actuator again, and install linkage to the actuator. Crank the engine and measure the oil pressure. If oil pressure is still low, replace the actuator.

Procedure C: Magnetic Pickup

The magnetic pickup is used to sense engine speed. It is a single-pole, permanent-magnet generator made up of a coil of wire wound around a permanent magnet pole (Figure 1).

Fig. 1 SCHEMATIC OF MAGNETIC PICKUP

With the magnet placed close to the gear teeth, an AC voltage is generated as the gear teeth cut through the magnetic field. The amplitude and frequency of this voltage are proportional to engine speed. Signal conditioning electronics mounted on the speed pickup convert the AC voltage to a digital output that approximates a square wave of constant amplitude. The locomotive control converts the frequency of that square wave into a measured speed value for use in governing the engine. The gap between the gear and magnetic pickup pole piece must be adjusted to avoid interference yet remain close enough to assure a valid signal. This clearance is normally 0.89 plus or minus 0.13 mm (.035 plus or minus .005 in).

For field installation, this gap may be set by turning pickup into threads until magnet is against the gear tooth while the engine is stopped.

Now back pickup out 1/2 to 3/4 turn for the 3412 and 3500 engines, or 1 1/4 ± 1/8 turn for 3600 engines.

Tighten the locknut to 70 ± 14 N·m (50 ± 10 lb ft).

The magnetic pickup used with the electronic locomotive control (6T4361) is NOT interchangeable with the pickups used with other electronic governors on Caterpillar engines. The other pickups do not have the built-in signal conditioning electronics required by the locomotive control.

Troubleshooting The Magnetic Pickup

If the electronic locomotive control does not receive a valid signal from the magnetic speed pickup, it will automatically shut the engine down or not allow it to start. In some cases, it may be possible to re-start the engine, but it will shut down within a few seconds. In any event, if the speed sensor is not working, the diagnostic display on the locomotive control will indicate a speed sensor fault. If this happens, check the wiring harness and make sure all connections are tight. Next, check the gap between the speed pickup and gear as outlined above. If these items are OK and the control still indicates a speed sensor fault, then the magnetic pickup must be replaced.

Procedure D: Rack Position Sensor

The rack position sensor is used to sense engine load by measuring fuel system rack position. It is a linear potentiometer used in a voltage divider configuration to produce a voltage proportional to rack position. Analog to digital converter electronics located near the sensor convert this voltage to a digital signal. This signal is supplied to the locomotive control through the wiring harness. The analog to digital converter is wired directly to the sensor without the use of connectors. This configuration avoids loss of accuracy due to voltage drops across faulty connectors. The sensor and A/D converter must be replaced together if either is found to be defective.

Fig. 1 RACK POSITION SENSOR

Correct adjustment is achieved when a reference rack position causes a corresponding reference voltage level to be output from the rack sensor to the A/D converter. The sensor output voltage is changed by adjusting the distance between the sensor body and the rack indicator lever (figure 1). LED indicators on the control box (figure 2) indicate the correct adjustment of the sensor.

Fig. 2 RACK SENSOR CALIBRATION LED DISPLAY

Disassemble Rack Sensor

1. Remove bolts (1) and remove cover (2).

2. Remove bolts (3) that hold converter module (4) to rack sensor housing (5).

3. Remove rubber grommet (6) and locknut (7).

4. Remove adjusting sleeve (8) from rack sensor housing (5).

5. Remove sensor body (9) from rack sensor housing (5).

6. Remove spring (10) and locknut (7) from sensor body (9).

7. Remove o-ring (11) from rack sensor housing (5).

Assemble Rack Sensor

1. Install o-ring (11) in rack sensor housing (5).

2. Install locknut (7) over sensor body (9) and install spring (10) on sensor body.

3. Put a small amount of engine oil on o-ring (11). Install sensor body (9) in the rack sensor housing.

4. Be sure washer (12) is in position on sensor body (9) and install adjusting sleeve (8) in rack sensor housing.

5. Put locknut (7) on adjusting sleeve (8) and install rubber grommet (6) over wires.

6. Install converter module (4) on rack sensor housing (5).

NOTE: If the rack sensor assembly will be immediately installed on the engine, do not install the cover. The rack sensor assembly must be calibrated before the engine is started.

7. Install rubber grommet (6) to cover (2) and install cover on rack sensor housing (5).

Adjusting The Rack Position Sensor

1. Perform the following steps with the engine stopped.

2. Be sure the rack stop is set to the correct fuel setting.

3. Apply electrical power to the control.

4. Remove four bolts attaching protective cover. Carefully slide grommet out of the slot in the bottom of the cover and set the cover aside.

RACK POSITION SENSOR

5. Loosen lock nut on adjusting sleeve.

6. Remove plug on Personality Module marked 'CAL' (figure 3) and turn calibration switch to the calibrate position (clockwise). The LED display on the control box should indicate that the control is in the calibration mode. As shown in figure 2, there are eight LED's arranged vertically on the diagnostic display. The fourth LED from the bottom (just below wheel slip LED) is lit when the control is in the calibration mode. The bottom three LED's indicate when the rack sensor calibration is correct or if not, which direction the adjustment sleeve must be turned to make it correct.

7. Hold the rack against the load stop screw. The load stop must be adjusted according to specifications before the rack sensor is calibrated.

8. Turn the sensor adjusting sleeve until the 'CAL ADJ CORRECT' LED is lit on the control. Turn sleeve in (clockwise) if the 'TURN CAL ADJ IN' LED is lit. Turn sleeve out (counter-clockwise) if the 'TURN CAL ADJ OUT' LED is lit. See figure 2 for correct interpretation of the LED display.

9. Tighten lock nut to 55 ± 7 N·m (40 ± 5 lb ft).

10. Return calibration switch to normal position. The LED display on the control should indicate normal operation (fourth LED from the bottom will go out). Replace plug over the calibration switch.

11. Slide grommet into the bottom side of the protective cover and reinstall cover using the four bolts.

Fig. 3 PERSONALITY MODULE

Procedure E: Wheel Slip Ramp Rate Adjustment

The wheel slip down ramp potentiometer controls the rate at which power is removed during a wheel slip condition. The wheel slip up ramp controls the rate at which power is restored following a wheel slip. To adjust these it is necessary to operate the locomotive against a load which will cause wheel slip. Remove the plugs covering the adjustment potentiometers. Adjust the Ramp Down potentiometer until the power is removed rapidly enough to stop slip rapidly. Adjust Ramp Up to cause power to restore rapidly but without causing slip immediately. Replace plugs over adjustment potentiometers.

PERSONALITY MODULE

Procedure F: Low Idle Adjustment

The Low idle adjustment potentiometer permits adjustment of the speed of the lowest notch on the locomotive. In general it will be factory preset to the nominal value specified for that notch. Adjustment of the potentiometer allows a limited adjustment ± 25 RPM from the specified speed. This adjustment is not normally necessary. Should the locomotive have a resonance problem at the specified speed, adjust the speed up or down to change the speed away from resonance.

1. Remove the plug marked P1 from the personality module.

2. With the engine running adjust the potentiometer visible under the plug with a small screwdriver, clockwise to increase speed, counterclockwise to reduce speed until the locomotive is no longer in resonance or until the engine speed is as desired.

3. Replace the plug back onto the personality module.

PERSONALITY MODULE

Procedure G: Voltage And Current Signal Adjustments

The voltage and current signals, if used, must be properly adjusted in order to permit correct operation of the control system. The following procedure is intended to guide in accurately adjusting the signal level into the control system.

1. Set-up engine to run on load banks at full load.

NOTE: Take care that in this setup the generator voltages and currents are still provided to the electronic control system.

2. Run locomotive at the highest notch against the load banks. Measure and record the generator voltage and current.

With Connector J1 connected to the Control box, measure the DC voltage applied by the locomotive electrical system to Connector J1 pin 11 (Voltage Sense Input) with respect to - Battery Voltage.

For DC generators:

Adjust the voltage sensing circuit until the voltage at J1 pin 11 is equal to:

For AC generators:

Adjust the voltage sensing circuit until the voltage at J1 pin 11 is equal to:

With connector J1 connected to the Control box, measure the DC voltage applied by the locomotive electrical system to Connector J1 pin 10 (Current Sense Input) with respect to - Battery Voltage.

For DC generators:

Adjust the current sensing circuit until the voltage at J1 pin 10 is equal to:

For AC generators:

Adjust the current sensing circuit until the voltage at J1 pin 10 is equal to:

Procedure H: Personality Module Replacement

The personality module is used to provide information to the Electronic Locomotive Control on the specific engine, generator, and control system configuration. For a particular locomotive, use only personality modules of exactly the same part number as the original. Failure to do this may result in serious damage to the engine, generator, and other attachments.

The personality module is located on the electronic control module and is identified as the small module bolted to the larger control box.

ELECTRONIC LOCOMOTIVE CONTROL BOX
(1) Personality module. (2) Threaded holes.

1. Remove the 4 bolts from the 4 corners of personality module (1).

2. Install 2 of the removed bolts into the threaded holes (2) located at the midpoints of the short sides of the personality module and tighten until the personality module can be easily removed.

3. Carefully clean all remaining gasket material from the mounting face on the control module.

4. Apply new gasket material to the mounting face of the new personality module to be used.

5. Insert 2 bolts through 2 diagonally opposed holes of the personality module to serve as guides.

6. Mount the personality module on the control module taking care to properly line up the connector and avoid smearing the gasket material. The 2 guide bolts will ease in avoiding smearing and connector line-up.

7. Tighten the 2 guide bolts and install and tighten the other 2 mounting bolts.

8. Low idle trim, and the wheel slip up and wheel slip down rates may need to be reset before the locomotive is released for service. (See procedures E and F)

Use the schematic that follows to make a Service Tool for making voltage and current measurements at connected VE connectors.

A 6V3001 Crimping Tool and 6V4810 VE Connector Tool Group will also be needed.