Electronic Modular Control Panel II (EMCP II) Caterpillar

Illustration 1	g00518564
System Schematic For Starting Motor Relay

Illustration 2	g00686852
Junction Box For ETR Generators Without The Cover (1) Starting Motor Magnetic Switch (SMMS).

Two starting motor magnetic switches (SMMS) are used in a system with two starting motors. One switch is used for each starting motor.

Test Procedure

1. From beneath the control panel, disconnect the jumper wire between terminal TS1-4 and TS1-5 in the generator housing. From beneath the control panel use the 7X-1710 Multimeter Probes in order to measure the resistance between connector contact TS1-5 and contact TS1-2. The resistance should measure the following value.
   • 26 to 33 ohms for single starting motor systems

   • 13 to 17 ohms for dual starting motor systems

   If the resistance is NOT correct, replace the defective magnetic switch. If the resistance is correct, proceed to Step 2.

2. Disconnect the cable that is going from the pinion solenoid to the starting motor. Do this procedure on both starting motors of a dual starting system.

3. Connect a DC voltmeter. Connect the positive cable to terminal TS1-24 and the negative cable to TS1-25 in the generator housing. If the second magnetic switch is tested in a dual starting motor system, then connect the negative cable to terminal TS1-26.

   Note: The jumper wire of Step 4 can remain connected for only ten seconds.

4. Temporarily connect a jumper wire from TS1-1 to TS1-5 in the generator housing. Disconnect this wire immediately after the voltage is measured. Do NOT leave the wire connected more than ten seconds. The correct measurement changes from approximately 24 DCV to approximately 2 DCV.

If the voltage is greater than 2.0 DCV, then replace the magnetic switch. If the switch passes the requirements of Step 1 and Step 4, the switch is functioning correctly. Reconnect the wires and cables that were removed in this procedure.