3512B Generator Set Engine Caterpillar

When the local emergency stop switch on the control panel is depressed, the coils of relay "R4" and relay "R4A" are energized. The contacts of relay "R4" keep the coils of relay "R4" and relay "R4A" energized until the Engine Control Switch (ECS) is cycled to the OFF position. The contacts of relay "R4A" energize the coils of relays "R2" and "R2A". When relays "R2" and "R2A" are energized, power is removed from the engine's primary Electronic Control Module (ECM) and the engine's secondary ECM. The primary ECM and the secondary ECM will power down. The injection signals to the injector solenoids will stop. The emergency stop lamp on the control panel will illuminate.

The contact of relay "R4A" also supplies power to terminal 3 of the connector for the timer. When power is applied to terminal 3 of the connector for the timer, the timer will activate. The timer outputs 24 VDC to terminal 6 of the connector for the timer for 2.5 seconds. The 24 VDC from terminal 6 of the connector for the timer is applied to the coil of the "Air Shutoff Switch (ASOS)". The contact of the "ASOS" energizes the air shutoff solenoids. The timer will output voltage to the coil of the "ASOS" for approximately 2.5 seconds. The "ASOS" will then deactivate and power is removed from the air shutoff solenoids. This prevents damage to the air shutoff solenoids. A normally open switch at the air shutoff valves will close when the air shutoff solenoid activates the air shutoff valve. The switch input to the ECM notifies the ECM that the air shutoff valves are closed. The ECM will not send injection signals to the injector solenoids until the switch inputs from the air shutoff valves indicate that the valves are open.

Relay "R3A" and relay "R3" are energized at the same time as the "ASOS" through terminal 3 of the diode assembly. Terminal 3 of the diode assembly will energize relay "R3A" and relay "R3" for 2.5 seconds. The relays "R3A" and "R3" will de-energize after 2.5 seconds. The overspeed indicator on the control panel will illuminate for 2.5 seconds.

In order to start the engine after an emergency stop condition, the ECS must be turned to the OFF position. This resets the ECM and the air shutoff timer. In addition to turning the ECS to the OFF position, the operator must manually open the air shutoff valves before starting the engine.

Illustration 1	g01645473
Typical example

Illustration 2	g01624906
Terminal locations for the following connectors A-C90/P-C1 and A-C91/P-C2 Connectors for the power distribution panel, A-C2/J-C2/J-C1 Right hand cross over harness and C-C2/J-C1/J-C2 Left hand cross over harness (Terminal B) Emergency stop signal 354-BK(Black) (Terminal E) 24 VDC 120-BK(Black) (Terminal H) Return for the air shutoff solenoid H708-BK(Black) (Terminal I) Drive for the air shutoff solenoid G708-BK(Black)

Illustration 3	g01322359
Terminal locations for the C-C17/F-C1/F-C2/G-C6 Connectors for a LH Control panel (Terminal 11) 24 VDC 120-BK(Black) (Terminal 12) Emergency stop signal 354-BK(Black)

Illustration 4	g01322442
Terminal locations for the C-C1/E-C1/E-C2 Left hand cross over harness (Terminal f) 24 VDC 120-BK(Black) (Terminal m) Emergency stop signal 354-BK(Black)

Illustration 5	g01622856
Connector locations (1) A-C1/E-C2/E-C1 Right hand cross over harness (2) A-C2/J-C2/J-C1 Right hand cross over harness (3) A-C90/P-C1 Connectors for the power distribution panel (4) A-C91/P-C2 Connectors for the power distribution panel (5) A-C60 Connector for the prelube motor (6) A-C92/F-C1/F-C2/G-C6 Connectors for a RH Control panel (7) C-C22 Primary ECM connector P2 (8) C-C15 Primary ECM connector P1 (9) C-C28 Secondary ECM connector P2 (10) C-C29 Secondary ECM connector P1 (11) C-C47 Connector for the power relay panel (12) C-C17/F-C1/F-C2/G-C6 Connectors for a LH Control panel (13) C-C18/(TB-C1 customer or L-C1/L-C2 EMCP 3) connectors (14) C-C2/J-C1/J-C2 Left hand cross over harness (15) C-C1/E-C1/E-C2 Left hand cross over harness

Test Step 1. Inspect the Electrical Connectors and the Wiring

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the OFF position.

3. Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Check the allen head screw on each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

4. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.

5. Check the harness and the wiring for abrasion and for pinch points.

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.

Results:

• OK - The harness and wiring appear to be OK. Proceed to Test Step 2.

• Not OK - There is a problem in the connectors and/or wiring.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.

  STOP

Test Step 2. Test the Circuit for the Local Emergency Stop Switch

1. Turn the circuit breaker for the battery to the ON position.

2. Turn the ECS to the STOP position.

3. Activate the local emergency stop switch on the control panel.

4. Monitor the air shutoff solenoids.

5. Deactivate the local emergency stop switch.

Expected Result:

The air shutoff solenoids activated.

Results:

• OK - The air shutoff solenoids activated correctly.

  Repair: The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - The air shutoff solenoids failed to activate. Proceed to Test Step 3.

Test Step 3. Check for Voltage from the "ASOS" at the Connector P-C1 for the Power Distribution Panel

1. Turn the ECS to the OFF position.

2. Remove wire G708-BK(Black) from terminal "I" of connector A-C90. Install a wire jumper into the connector for wire G708-BK(Black).

3. Turn the ECS to the STOP position.

4. Activate the local emergency stop switch.

5. Monitor the voltage on the wire jumper in terminal I at connector A-C90 of the rigid harness. Refer to Illustration 1 for a schematic of the circuit.

6. Activate the local emergency stop switch.

7. Return all wiring to the original configuration.

Expected Result:

The voltage measures 24 ± 3 VDC for approximately 2.5 seconds.

Results:

• OK - The voltage measures 24 ± 3 VDC for approximately 2.5 seconds. The circuit is operating correctly to this point. Proceed to Test Step 7.

• Not OK - The voltage did not measure 24 ± 3 VDC for approximately 2.5 seconds. Proceed to Test Step 4.

Test Step 4. Test for Voltage to the Coil of Relay "R4A" at the Connector P-C2 for the Power Distribution Panel

1. Turn the ECS to the OFF position.

2. Remove wire 354-BK(Black) from terminal "B" of connector A-C91.

3. Turn the ECS to the STOP position.

4. Activate the local emergency stop switch.

5. Monitor the voltage on wire 354 at connector A-C91 of the rigid harness.

6. Deactivate the local emergency stop switch.

7. Return all wiring to the original configuration.

Expected Result:

The voltage measures 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC. The circuit is operating correctly to this point. Proceed to Test Step 5.

• Not OK - No voltage was measured. Proceed to Test Step 11.

Test Step 5. Test for Voltage at the Coil of the "ASOS"

1. Turn the ECS to the OFF position.

2. The input to the coil of the "ASOS" is wire T708-BK(Black) from terminal 6 of the timer. Remove wire T708-BK(Black) from the "ASOS".

3. Connect a voltmeter between wire T708-BK(Black) from the "ASOS" and the engine ground.

4. Turn the ECS to the STOP position.

5. Activate the local emergency stop switch.

6. Monitor the voltage on the voltmeter.

7. Deactivate the local emergency stop switch.

8. Return all wiring to the original configuration.

Expected Result:

The voltage measures 24 ± 3 VDC for approximately 2.5 seconds.

Results:

• OK - The voltage measures 24 ± 3 VDC for approximately 2.5 seconds. The circuit is operating correctly to this point. Proceed to Test Step 6.

• Not OK - The voltage did not measure 24 ± 3 VDC. Proceed to Test Step 8.

Test Step 6. Check for Voltage from the "ASOS" to the Air Shutoff Solenoids

1. Turn the ECS to the OFF position.

2. Disconnect wire G708-BK(Black) from the "ASOS".

3. Connect a voltmeter to the empty terminal on the "ASOS". Connect the other lead from the voltmeter to engine ground.

4. Turn the ECS to the STOP position.

5. Activate the local emergency stop switch.

6. Monitor the voltage on the voltmeter.

7. Deactivate the local emergency stop switch.

8. Reconnect wire G708-BK(Black) to the "ASOS".

Expected Result:

The voltage measures 24 ± 3 VDC for approximately 2.5 seconds.

Results:

• OK - The voltage measures 24 ± 3 VDC for approximately 2.5 seconds. The circuit is operating correctly to this point.

  Repair: Repair the wire G708-BK(Black) between the "ASOS" and wire G708-BK(Black) on pin I at connector P-C1 of the rigid harness.

  STOP

• Not OK - The voltage did not measure 24 ± 3 VDC for approximately 2.5 seconds.

  Repair: Verify that 24 ± 3 VDC is present on wire K708-BK(Black) at the normally open contacts of the "ASOS". If voltage is not present on wire K708-BK(Black), check the wire K708-BK(Black) and the circuit breaker for the air shutoff for problems.

  If voltage is present on the wire K708-BK(Black), check wire 220-BK(Black) on the coil of the "ASOS" for continuity to the −Battery. If necessary, repair the wire or replace the wire. If wire 220-BK(Black) is OK and voltage is present on wire K708-BK(Black), replace the "ASOS".

  STOP

Test Step 7. Check the Voltage at the Connector for the Air Shutoff Solenoids

1. Turn the ECS to the OFF position.

2. Disconnect the connector for the air shutoff solenoids. Disconnect the connector for the right and left sides of the engine.

3. Connect a voltmeter between wire G708-BK(Black) on the connector for the air shutoff solenoid and the engine ground.

4. Turn the ECS to the STOP position.

5. Activate the local emergency stop switch.

6. Monitor the voltage on the voltmeter.

7. Deactivate the local emergency stop switch.

8. Reconnect the connectors for the air shutoff solenoids.

Expected Result:

The voltage measures 24 ± 3 VDC for approximately 2.5 seconds.

Results:

• OK - The voltage measures 24 ± 3 VDC for approximately 2.5 seconds. The circuit is operating correctly to this point.

  Repair: Check the wire H708-BK(Black) from terminal A of the connector for continuity to the −Battery. If the wire H708-BK(Black) to the −Battery terminal is OK, replace the air shutoff solenoid. Verify that the circuit operates correctly.

  If the wire H708-BK(Black) does not have continuity to the −Battery from terminal A of the connector, check for continuity on wire H708-BK(Black) on pin H at connector P-C1/A-C90 of the rigid harness to −Battery. If the wire H708-BK(Black) does not have continuity to the −Battery from pin H at connector P-C1 of the rigid harness, verify that the breaker for the air shutoff is not tripped.

  STOP

• Not OK - The voltage did not measure 24 ± 3 VDC for approximately 2.5 seconds. System voltage was not available at the solenoid connector.

  Repair: There is a problem in the wiring between the connector for the air shutoff solenoids and wire G708-BK(Black) on pin I at connector P-C1/A-C90 of the rigid harness. Repair the connectors or wiring and/or replace the connectors or wiring.

  STOP

Test Step 8. Check the Voltage at the Contact of Relay "R4A"

1. Turn the ECS to the OFF position.

2. Disconnect wire T120-BK(Black) from terminal 87 of relay "R4A".

3. Connect a voltmeter between terminal 87 of relay "R4A" and the engine ground.

4. Turn the ECS to the STOP position.

5. Activate the local emergency stop switch.

6. Monitor the voltage on the voltmeter.

7. Deactivate the local emergency stop switch.

8. Turn the ECS to the OFF position.

9. Reconnect wire T120-BK(Black).

Expected Result:

The voltage measures 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC. Proceed to Test Step 9.

• Not OK - The voltage did not measure 24 ± 3 VDC. Proceed to Test Step 10.

Test Step 9. Check the Voltage at Terminal 6 of the Connector for the Timer

1. Turn the ECS to the OFF position.

2. Disconnect wire T708-BK(Black) from terminal 6 of the connector for the timer.

3. Connect a voltmeter between terminal 6 of the connector for the timer and engine ground.

4. Turn the ECS to the STOP position.

5. Activate the local emergency stop switch.

6. Monitor the voltage on the voltmeter.

7. Deactivate the local emergency stop switch.

8. Return all wiring to the original configuration.

Expected Result:

The voltage measures 24 ± 3 VDC for approximately 2.5 seconds.

Results:

• OK - The voltage measures 24 ± 3 VDC for approximately 2.5 seconds.

  Repair: Repair the wire T708-BK(Black) between the "ASOS" and terminal 6 of the timer.

  STOP

• Not OK - The voltage did not measure 24 ± 3 VDC for approximately 2.5 seconds.

  Repair: Check for 24 ± 3 VDC on terminal 3 of the connector for the timer.

  If voltage is not present on terminal 3, repair the wire T120-BK(Black) between terminal 87 of relay "R4A" and terminal 3 of the connector for the timer.

  If voltage is present on terminal 3 of the connector for the timer, verify that wire 220-BK(Black) on terminal 2 of the connector for the timer has continuity to the −Battery. If wire 220-BK(Black) does not have continuity to the −Battery, repair the wire.

  Verify that 24 ± 3 VDC is present on terminal 1 of the connector for the timer. If 24 ± 3 VDC is not present on terminal 1 of the connector for the timer, verify that the ECS is not in the "OFF" position. Verify that the "MPD" breaker is not tripped. Check the normally closed contact of relay "R1" for proper operation. Check the wire 120-BK(Black) between terminal 1 of the connector for the timer and relay "R1" for damage. Check the wire A120-BK(Black) between relay "R1" and the "MPD" breaker for damage. If necessary, repair the wires.

  If the voltage is present on terminal 1 and 3 of the timer and wire 220-BK(Black) is OK, replace the timer.

  STOP

Test Step 10. Check the Voltage at the Coil of Relay "R4A"

1. Turn the ECS to the OFF position.

2. Disconnect wire 354-BK(Black) from terminal 86 of relay "R4A".

3. Connect a voltmeter between wire 354-BK(Black) on terminal 86 of relay "R4A" and the engine ground.

4. Turn the ECS to the STOP position.

5. Activate the local emergency stop switch.

6. Monitor the voltage on the voltmeter.

7. Deactivate the local emergency stop switch.

8. Reconnect wire 354-BK(Black).

Expected Result:

The voltage measures 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC.

  Repair: Check wire 220-BK(Black) on the coil of the "R4A" relay for continuity to the −Battery. If necessary, repair the wire or replace the wire.

  Check for 24 ± 3 VDC on wire 120-BK(Black) on terminal 30 of relay "R4A". If 24 ± 3 VDC is not present on wire 120-BK(Black), verify that the ECS is not in the "OFF" position. Verify that the "MPD" breaker is not tripped. Check the normally closed contact of relay "R1" for proper operation. Check the wire 120-BK(Black) between terminal 30 of the relay "R4A" and relay "R1" for damage. Check the wire A120-BK(Black) between relay "R1" and the "MPD" breaker for damage. If necessary, repair the wires.

  If wire 220-BK(Black) is OK and voltage is present on wire 120-BK(Black) on terminal 30, replace relay "R4A".

  STOP

• Not OK - The voltage did not measure 24 ± 3 VDC.

  Repair: Repair the wire 354-BK(Black) between the coil of the "ASOS" and the connector P-C2/A-C91 on the power distribution panel.

  STOP

Test Step 11. Check the Voltage from the Local Emergency Stop Switch to Relay "R4A"

1. Turn the ECS to the OFF position.

2. Disconnect wire 354-BK(Black) from the local emergency stop switch.

3. Connect a voltmeter to the empty terminal on the local emergency stop switch. Connect the other lead from the voltmeter to engine ground.

4. Turn the ECS to the STOP position.

5. Activate the local emergency stop switch.

6. Monitor the voltage on the voltmeter.

7. Deactivate the local emergency stop switch.

8. Reconnect wire 354-BK(Black).

Expected Result:

The voltage measures 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC.

  Repair: Repair the wire 354-BK(Black) between the local emergency stop switch and the wire 354-BK(Black) on pin B at connector P-C2/A-C91 of the rigid harness. Refer to Illustration 1 for a schematic of the circuit and the interconnecting connectors of the circuit.

  STOP

• Not OK - The voltage did not measure 24 ± 3 VDC. Proceed to Test Step 12.

Test Step 12. Check the Voltage to the Local Emergency Stop Switch

1. Turn the ECS to the OFF position.

2. Connect a voltmeter between wire 120-BK(Black) on the local emergency stop switch and engine ground.

3. Turn the ECS to the STOP position.

4. Monitor the voltage on the voltmeter.

Expected Result:

The voltage measures 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC.

  Repair: Replace the local emergency stop switch.

  STOP

• Not OK - The voltage did not measure 24 ± 3 VDC.

  Repair: Check the wire 120-BK(Black) on pin E at connector P-C2/A-C91 of the rigid harness between the connector and the local emergency stop switch for damage. Refer to Illustration 1 for a schematic of the circuit and the interconnecting connectors of the circuit.

  Verify that the ECS is not in the "OFF" position. Verify that the "MPD" breaker is not tripped. Check the normally closed contact of relay "R1" for proper operation. Check the wire A120-BK(Black) between relay "R1" and the "MPD" breaker for damage. If necessary, repair the wires.

  STOP