3306B Industrial Engine Caterpillar

Contactor Switch for Oil Pressure

Test Procedure

Table 1

Tools Needed
8T-0853	Pressure Indicator (0 to 60 psi)	1
3B-7734	Pipe Nipple	1
3B-6483	Cap	1
3B-7263	Pipe Nipple	2
3B-9389	Shutoff Cock Fitting	2
1F-9369	Tee	2
004-4914	Tee	1
5K-3772	Hose Assembly	2
8T-0500	Circuit Tester	1

Illustration 1	g00510384
Test Equipment (1) 8T-0853 Pressure Indicator (2) 3B-7734 Pipe Nipple (3) 3B-6483 Cap (4) Oil Supply Line (5) 3B-7263 Pipe Nipple (6) 3B-9389 Shutoff Cock Fitting (7) 3B-9389 Shutoff Cock Fitting (8) 1F-9369 Service Tee (9) 5K-3772 Hose Assemblies (10) 004-4914 Tee

1. Remove the cover of the contactor switch and disconnect the wires from the normally closed (B or Blue) terminal.

2. Disconnect the oil supply line from the contactor switch and install the test equipment, as shown.

3. Connect the 5K-3772 Hose (9) from tee (10) to the contactor switch. Put the end of the other 5K-3772 Hose (9) in a pan.

4. Connect the 8T-0500 Circuit Tester between the common terminal and the normally closed terminal. The light of the circuit tester will be activated.

5. Close 3B-9389 Shutoff Cock Fitting (7) and open the other 3B-9389 Shutoff Cock Fitting (6) .

6. Look at the pressure indicator, start the engine and run it at low idle rpm. The light must go out, with an increase in oil pressure, at the specification of the switch.

7. Close 3B-9389 Shutoff Cock Fitting (6) and slowly open the other 3B-9389 Shutoff Cock Fitting (7). The light must be activated, with a decrease in oil pressure, at the specification of the switch.

8. Stop the engine.

9. Connect the wire(s) to the normally closed terminal.

10. On contactor switches with a button or a control knob either push the button or turn the knob to the OFF position.

11. Close 3B-9389 Shutoff Cock Fitting (7) and open the other 3B-9389 Shutoff Cock Fitting (6) .

12. Start the engine and run it at low idle rpm.

13. Put a jumper wire between the common terminal and the normally closed terminal. This will check the system beyond the contactor switch.

14. Remove the jumper wire.

Adjustment of Micro Switch Type Contactor

Illustration 2	g00510411
Contactor Switch For Oil Pressure (11) Set for start button (12) Adjustment screw (13) Spring (14) Locknut (15) Contact button

1. Loosen locknut (14) and turn adjustment screw (12) counterclockwise to make a decrease in the tension of spring (13) .

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Illustration 3	g00510412
Wiring Connections (D) Normally closed B terminal (E) Normally open W terminal (F) Common R terminal

2. Disconnect the wires from the normally closed terminal of the switch.

3. Start the engine and run it at low idle rpm.

4. Close 3B-9389 Shutoff Cock Fitting (6) and slowly open the other 3B-9389 Shutoff Cock Fitting (7) until the pressure indicator shows the pressure specification at which the switch must close with a decrease in pressure. Close the 3B-9389 Shutoff Cock Fitting (7) .

5. Ensure the set for start button (13) is in the RUN position.

6. Connect the 8T-0500 Circuit Tester between the common terminal and the normally closed terminal. The light of the circuit tester must not be activated.

7. Turn adjustment screw (12) clockwise until the light of the circuit tester is activated.

8. Tighten the locknut.

9. To check the adjustment, close 3B-9389 Shutoff Cock Fitting (7) and open the other 3B-9389 Shutoff Cock Fitting (6) .

10. Connect the wires to the normally closed terminal.

11. Close 3B-9389 Shutoff Cock Fitting (6) and slowly open the other 3B-9389 Shutoff Cock Fitting (7) until the engine stops or the alarm operates.

12. The pressure indicator must show the correct pressure specification of the switch as the engine stops or the alarm operates.

Contactor Switch for Water Temperature

Method of Checking

Table 2

Tools Needed
Fabricated Heat Sink	1
2F-7112	Thermometer	1
3J-5389	Plug	1
8T-0500	Circuit Tester	1

Illustration 4	g00510413
Heat Sink

1. Make a heat sink as shown. Material can be brass, steel or cast iron. Drill a 23/32 inch hole through the plate and use a tap to make 1/2 inch NPT threads.

2. Put marks on the two contactor wires that connect the contactor to he circuit. Disconnect the two wires.

3. Remove the contactor and install a 3J-5389 Plug. Install the contactor switch in the heat sink.

4. Put the heat sink and contactor in water as shown. Use blocks to support the heat sink at surface level.

5. Connect the 8T-0500 Circuit Tester between the wires that connected the contactor to the circuit.

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Illustration 5	g00510414
Test of Contactor Switch (1) 2F-7112 Thermometer (2) Fabricated heat sink

6. Put the 2F-7112 Thermometer in the water.

7. Use a torch to heat the water to the temperature range at which the contactor must activate. If the circuit tester light does not come on within the temperature range given in the Specifications, make a replacement of the contactor.

8. Let the water temperature go down. If the circuit tester light does not go out within the temperature range given in the Specifications, replace the contactor.

Pressure Switch with Time Delay

Table 3

Tools Needed
8T-0848	Indicator	1
8T-0500	Circuit Tester	1

1. Disconnect the wires from pressure switch.

2. Remove the pressure switch from the junction block.

3. Install an elbow, a short nipple, a shutoff valve, a short nipple and tee as shown in place of the pressure switch. Ensure that the valve is closed.

4. Install the pressure switch and a 8T-0848 Indicator in the open ends of the tee as shown.

5. Connect the 8T-0500 Circuit Tester between the terminals of the pressure switch.

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Illustration 6	g00510385
Typical example of test tools installed.

6. Start the engine. Open the shutoff valve a small amount. Look at the pressure on the 8T-0848 Indicator. When the pressure gets to the range given in the Specifications, the circuit tester light must go on.

7. Close the shutoff valve. Stop the engine. Open the shutoff valve a small amount. Look at the pressure on the 8T-0848 Indicator . When the pressure gets to the range given in the Specifications, close the valve. After five minutes open the valve fully. The circuit tester light must stay on a minimum of 30 seconds and a maximum of 15 minutes after the valve is fully opened.

Shutoff Solenoids

1. Ensure the linkage to which the solenoid is connected does not give more than the normal amount of restriction.

2. Connect a voltmeter between the terminals of the solenoid.

3. Activate the solenoid circuit. If the voltage shown on the meter is less than the needed voltage, the circuit has a failure. Check the other components of the circuit. If the voltage is the same or more than the needed voltage, replace the solenoid.

Table 4

System Voltage	Needed Voltage
6	5.0
12	10.5
24	21.5
32	29.0

Contactor Switch for Overspeed

The original setting of the contactor switch for overspeed will stop the engine when the engine rpm is more than 18 percent above full load rpm. DO NOT check the adjustment of the contactor switch on the engine.

Table 5

Tools Needed
6v3121	Multitach Group	1
8T0500	Circuit Tester	1
5L2277	Adapter	1
	Reversible Variable Speed Drill	1

1. Connect the 6V-2100 Multitach of the 6V-3121 Group to the 5P-7360 Generator Assembly .

2. Connect the 5L-2277 Adapter to the contactor switch and generator assembly.

3. Install the variable speed drill to the adapter.

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Illustration 7	g00510068
Overspeed contactor switch (1) Reset button (2) Lock screws

4. Connect the 8T-0500 Circuit Tester between the N.O. and the C terminals of the contactor switch. The light must be off. If the light is on, push reset button (1) .

5. Gradually increase the rpm. Read the rpm on the tachometer at the moment the light of the circuit tester is activated. The reading will give the engine rpm (2 rpm on the scale for each rpm the input shaft is turned).
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   Table 6

   Overspeed Adjustment
   Full Load ± 10 rpm	Overspeed Setting ± 25 rpm
   1000	1180
   1100	1298
   1200	1416
   1300	1534
   1400	1652
   1500	1770
   1600	1888
   1700	2006
   1800	2124
   1900	2242
   2000	2360
   2100	2478
   2200	2596
   2300	2714
   2400	2832

6. If needed, adjust the contactor switch by loosening lock screws (2). Turn the cap clockwise to lower the overspeed setting. Tighten the lock screws.

7. To check other components in the system, put a jumper wire between the C and N.O. terminals of the contactor switch.

Magnetic Pickup

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Illustration 8	g00345302
(1) Clearance (2) Locknut

1. Check the resistance of the magnetic pickup with the wires disconnected and the engine stopped. The resistance must be according to Specifications.

2. Start the engine. Check the voltage output of the magnetic pickup with the engine running at normal speed. The output must be according to Specifications.

   Note: If the voltage output is not correct according to Specifications, check for the correct clearance (1) between the magnetic pickup and the flywheel gear teeth.

3. If the operation of the magnetic pickup is correct according to the Specifications after the tests above, connect the wires and check the operation of the electronic speed switch.