FLOOR-STANDING SWITCHGEAR Caterpillar

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The bus bars and current transformer will have high voltage when the generator is in operation with the circuit breaker in the switchgear, closed. If the installation has more than one switchgear, and the other generators are in operation, the bus bars can have high voltage with the circuit breaker in the switchgear open. Be very careful when troubleshooting for voltage in the switchgear.

Before any work or tests are done in the switchgear, be sure you understand the principles of the operations.

Many of the electrical problems are caused by mechanical problems. Make a careful inspection of the total electric system and separate the mechanical problems from the electric problems. Find the operation problem and use the wiring diagrams with the troubleshooting to verify the probable cause.

All of the tests in the verification procedures can be made with a multi-tester (volt ohmmeter) but most of the tests can be made with a 5P7277 Tester for voltage and an 8S4627 Circuit Continuity Tester.

The relays with the clear covers are all the same and can be used in any relay socket.

It may be necessary to make a reference to the list of abbreviations for the names of the parts, switches, relays and lights that are on the schematics of the engine control group (ECG).

ACS

AUTOMATIC CONTROL SWITCH

AR

ARMING RELAY

ASO

AIR SHUTOFF SOLENOID

BATT.

BATTERY

BC

BATTERY CHARGER

CB

CIRCUIT BREAKER

CB/a

NORMALLY OPEN CIRCUIT BREAKER AUXILIARY CONTACT

CB/b

NORMALLY CLOSED CIRCUIT BREAKER AUXILIARY CONTACT

CBR

CIRCUIT BREAKER RELAY

CCR

CYCLE CRANK RELAY

CCM

CYCLE CRANK MODULE

CCT

CYCLE CRANK TIMER

CCR

COOLDOWN RELAY

CCM

COOLDOWN MODULE

CDT

COOLDOWN TIMER

CLL

COOLANT LEVEL LOW LIGHT (PREALARM)

CS

CIRCUIT BREAKER CONTROL SWITCH

CTS

CRANK TERMINATION SWITCH

C

CIRCUIT BREAKER CLOSED LIGHT

D

DIODE

DCA

DIRECT CURRENT READING AMMETER

DSS

DUAL SPEED SWITCH

FP

FUEL PRESSURE

GCR

GOVERNOR CONTROL RELAY

GOV.

GOVERNOR

GS

GOVERNOR SWITCH

GSM

GOVERNOR SPEED MOTOR

HWT

HIGH WATER TEMPERATURE LIGHT (PREALARM)

IC

INITIATIVE CONTACT

LCL

COOLANT LEVEL LOW SWITCH (PREALARM)

LFL

LOW FUEL LEVEL LIGHT (PREALARM)

LFS

LOW FUEL LEVEL SWITCH (PREALARM)

LOL

LOW OIL LEVEL LIGHT (PREALARM)

LWT

LOW WATER TEMPERATURE SWITCH

O

CIRCUIT BREAKER OPEN LIGHT

OCL

OVERCRANK LIGHT

OCR

OVERCRANK RELAY

OCT

OVERCRANK TIMER

OLL

OIL LEVEL LOW LIGHT (PREALARM)

OPL

LOW OIL PRESSURE LIGHT

OPP

LOW OIL PRESSURE PREALARM SWITCH

OPR

LOW OIL PRESSURE RELAY

OPS

LOW LUBE OIL PRESSURE SWITCH

OPT

OIL PRESSURE TIMER

OPTD

OIL PRESSURE TIME DELAY

OSL

OVERSPEED LIGHT

OSR

OVERSPEED RELAY

OSS

OVERSPEED SWITCH

PS

PRESSURE SWITCH

PSW

PRESSURE SWITCH

RPL

REVERSE POWER LIGHT

RPR

REVERSE POWER RELAY

RPRE

REVERSE POWER RELAY RESET SWITCH

RPRX

REVERSE POWER RELAY AUXILIARY

RR

RUN RELAY

SHTC

SHUNT TRIP COIL

SR

SHUTDOWN RELAY

SS

SHUTDOWN SOLENOID

SUP.

SUPPRESSOR

T

TRIP POSITION

WLT

LOW WATER TEMPERATURE LIGHT (PREALARM)

WTL

WATER TEMPERATURE LIGHT (HIGH)

WTP

HIGH WATER TEMPERATURE SWITCH (PREALARM)

WTR

WATER TEMPERATURE RELAY (HIGH)

WTS

WATER TEMPERATURE SWITCH (HIGH)

ENGINE CONTROL GROUP (ECG)

RELAY PRINTED CIRCUIT SOCKET BOARD

Problems

1. ENGINE WILL NOT CRANK.

2. ENGINE OVERCRANK DOES NOT OPERATE.

3. ENGINE WILL NOT TERMINATE CRANKING.

4. ENGINE RUNS BUT GOVERNOR SWITCH WILL NOT CHANGE ENGINE SPEED.

5. NO CONTROL VOLTAGE TO 2301 GOVERNOR.

6. ENGINE SPEED CONTROL (2301 GOVERNOR) WILL NOT CHANGE ENGINE SPEED.

7. NO VOLTAGE TO 2301 GOVERNOR.

8. ENGINE DOES NOT STOP WHEN OIL PRESSURE IS TOO LOW.

9. ENGINE DOES NOT STOP WHEN COOLANT TEMPERATURE IS TOO HIGH.

10. ENGINE DOES NOT STOP WHEN ENGINE SPEED (RPM) IS TOO FAST.

11. NOT NORMAL ENGINE CONDITION LIGHT IS NOT ON AFTER NOT NORMAL CONDITION STOPPED THE ENGINE.

12. ENGINE WILL NOT STOP WHEN AUTOMATIC CONTROL SWITCH (ACS) IS MOVED TO THE STOP POSITION.

13. ENGINE WILL NOT STOP WHEN AUTOMATIC CONTROL SWITCH (ACS) IS MOVED TO THE OFF/RESET POSITION.

14. ENGINE WILL NOT AUTOMATICALLY START.

15. ENGINE DOES NOT COOL ENOUGH BEFORE IT IS AUTOMATICALLY STOPPED.

16. BATTERY DOES NOT GET CHARGED WHEN ENGINE IS RUNNING.

Engine Will Not Crank.

Engine Overcrank Does Not Operate.

Engine Will Not Terminate Cranking.

Engine Runs But Governor Switch Will Not Change Engine Speed.

No Control Voltage To 2301 Governor.

Engine Speed Control (2301 Governor) Will Not Change Engine Speed.

No Voltage To 2301 Governor Actuator. - (Load Sharing Governor Control Option 6F)

Engine Does Not Stop When Oil Pressure Is Too Low.

Engine Does Not Stop When Coolant Temperature Is Too High.

Engine Does Not Stop When Engine Speed (RPM) Is Too Fast.

Not Normal Engine Condition Light Is Not On After Not Normal Condition Stopped The Engine.

Engine Will Not Stop When Automatic Control Switch (ACS) Is Moved To The Stop Position.

Engine Will Not Stop When Automatic Control Switch (ACS) Is Moved To The Off/Reset Position.

Engine Will Not Automatically Start.

Engine Does Not Cool Enough When It Is Automatically Stopped.

Battery Does Not Get Charged When Engine Is Running.

Relay Test

Needed: Circuit or continuity tester. Source of DC voltage (no less than 75% of voltage on relay cover).

RELAY
1. Cover. 2. Blades. 3. Contact (three).

1. Remove the relay from the engine control group (ECG) board.

2. There must be a circuit (continuity) for normally closed (NC) contacts (2) between blades 7 and 1, 8 and 2, 9 and 3. If there is no continuity between any of these pairs of blades, the relay is bad.

3. There must be no continuity (circuit) between blades 7 and 4, 8 and 5, 9 and 6. If there is continuity between any of these pairs of blades, the relay is bad.

RELAY BLADES AND CONTACTS (SCHEMATIC)

4. Put DC voltage, amount of volts shown on relay cover (1), between blades A and B to activate the coil and move (switch) the contacts.

5. With coil (A to B) activated, there must be continuity between blades 7 and 4, 8 and 5, 9 and 6. If there is no continuity between any of these pairs of blades, the relay is bad.

Automatic Control Switch (ACS) Test

The automatic control switch has 17 wire terminals. Each terminal has a number that is the same number as the contact in the switch that is connected to the terminal.

The switch is installed in the top panel of the switchgear with the two tie-bolts of the switch in a horizontal position. When the switch control (A) is in the MAN position (arrow on the control, down) there are no wire terminals on the bottom side of the switch.

AUTOMATIC CONTROL SWITCH (ACS)

There are wires that connect switch terminals 9 and 5, 9 and 16, 16 and 17. A wire from the engine control group (ECG) board TB2 connects to switch terminal 9.

When there is voltage at TB2 on the engine control group (ECG) board, there must be voltage on switch terminals 9, 5, 16 and 17. If there is no voltage at these terminals, either a wire connection is bad or a wire is disconnected or broken.

1. With switch control (A) in the MAN position, there is voltage at the four terminals (9, 5, 16, 17) and there must be voltage on only terminals 7, 11, 14 and 15.

2. With switch control (A) in the AUTO position, there is voltage at the four terminals (9, 5, 16, 17) and there must be voltage on only terminals 6, 10, 14 and 15.

AUTOMATIC CONTROL SWITCH (ACS) TERMINAL SCHEMATIC (From the Back)
1. through 17. Wire terminals (and contacts). A. Switch control in MAN position (arrow on control, down).

3. With switch control (A) in the STOP position, there is voltage at the four terminals (9, 5, 16, 17) and there must be voltage on only terminals 8, 12 and 15.

4. With switch control (A) in the OFF/RESET position, there is voltage at the four terminals (9, 5, 16, 17) and there must be voltage on only terminals 13 and 14.

An automatic control switch (ACS) can be tested, when it is not installed in the panel, with a continuity tester but switch terminals 5 to 9, 9 to 16 and 16 to 17 must be connected with wires (jumpers).

1. Switch control (A) in MAN position, there must be continuity between terminal 5 and only terminals 7, 11, 14 and 15.

2. Switch control (A) in AUTO position, there must be continuity between terminal 5 and only terminals 6, 10, 14 and 15.

3. Switch control (A) in STOP position, there must be continuity between terminal 5 and only terminals 8, 12 and 15.

4. Switch control (A) in OFF/RESET position, there must be continuity between terminal 5 and only terminals 13 and 14.