FILM-COMPUTER 2103270 - Caterpillar

Illustration 1 g00713118
Solenoid testA basic four terminal starting motor solenoid circuit is shown in Illustration 1. The two windings that are found in the solenoid are the hold-in winding and the pull-in winding. The windings can be checked by using the procedures that follow.Hold-in Winding Test
Illustration 2 g00713128
Hold-in winding test
Refer to Illustration 2 in order to make the connections to the solenoid. Disconnect all other leads to the solenoid.
Close the switch.Observe the reading on the multimeter. Use the battery load tester to adjust the battery voltage until the following voltages are obtained: 12 Volt System ... 10 Volts 24 Volt System ... 20 Volts
Observe the reading on the clamp-on ammeter.The following amperes should be observed: 12 Volt System ... 9.9 to 10.0 Amperes 24 Volt System ... 18.8 to 20.0 AmperesNote: A high reading indicates a shorted winding. A low reading indicates excessive resistance.
The hold-in winding can also be checked by measuring the resistance.Disconnect the batteries. Select the "200 ê" range on the multimeter. Connect one of the leads of the multimeter to the "S" terminal and connect the other lead to the "G" terminal.The following Ohms should be observed: 12 Volt System ... 1.05 0.05 Ohms 24 Volt System ... 1.05 0.05 Ohms
Replace the solenoid if any of the above readings are incorrect.Pull-in Winding Test
Illustration 3 g00713129
Pull-in winding test
Refer to Illustration 3 in order to make the connections to the solenoid. Disconnect all other leads to the solenoid.
Close the switch.Observe the reading on the multimeter. Use the battery load tester to adjust the battery voltage until the following voltages are obtained: 12 Volt System ... 2.5 Volts 24 Volt System ... 5 Volts
Observe the reading on the clamp-on ammeter.The following amperes should be observed: 12 Volt System ... 10.0 to 10.87 Amperes 24 Volt System ... 20.0 to 21.74 AmperesNote: A high reading indicates a shorted winding. A low reading indicates excessive resistance. To avoid excessive heat, do not leave the switch closed for more than 10 seconds at a time. The current will decrease as the heat increases.
The pull-in winding can also be checked by measuring the resistance. Perform the measurement with a voltmeter that reads 0.01 Ohm.Disconnect the batteries. Select the "200 ê" range on the multimeter. Connect one of the leads of the multimeter to the "S" terminal and connect the other lead to the "Mtr" terminal.The following Ohms should be observed: 12 Volt System ... 0.24 0.01 Ohms 24 Volt System ... 0.24 0.01 Ohms
Replace the solenoid if any of the above readings are incorrect.