Starter generator

[skreiner]

Can a starter generator be bench tested to see if it charges ? Thanks

 

[jbratton]

Yes. See below:

Mathew: Maybe start here?
Cub Cadet FAQ's #47

Easy Starter Generator Test

Here is an easy test for proper functioning of a Delco Starter-Generator (SG) unit. It can be done on the workbench or tractor with drive belt removed, and all wires removed from the F terminal. For the bench test you’ll need a battery, jumper cables, and a test lead. On the tractor, only the test lead is required.

The usual electrical failure on these units is that they will motor but not generate. This is caused by the generator field coil failing in open circuit mode. This test will check for electrical continuity through the generator coil without disassembly of the unit.

On the bench, ground the SG with the negative jumper cable to the (-) terminal of the battery, and connect the positive jumper to the A (armature) terminal and to the (+) terminal of the battery. Connect the test lead to the F (field) terminal of the SG unit, leaving the other end free. On the tractor, turn the key to start position. The SG should spin up rapidly and run like any DC electric motor. While running, take the test lead that’s connected to the F terminal and ground it to the frame of the SG. The unit should begin to slow down. This indicates the charge coil is good. If it does not slow down, the coil has failed in open circuit and will need replacement. Don’t continue this test for more than a few seconds as your running the charge coil fully shorted.

To understand why this works, check out the SG wiring diagram on this site:

Simpletractors.com