Troubleshooting Electromagnetic Clutches and Brakes

This 22 minute video will help you on your way to troubleshooting electromagnetic clutch and brake issues. The video is conveniently broken down into sections. You can jump to "Will not engage" at 4:21

Potential Problem Possible Reason Solution
No voltage going to the clutch. Wiring connector not seated properly. Pull apart and re-seat connector.
No voltage or low voltage coming from the battery. Check with voltmeter, battery should be 8-16 volts. (Assuming 12 volt battery.)
Defective charging system. Fix charging system.
Lead wire cut or broken internally. (Example) Fix or replace lead wire. If destroyed, replace clutch.
Fuse blown. Replace fuse.
Defective switch operating clutch. Replace the switch.
If voltage is going to the clutch, but the clutch will still not engage. Coil open or shorted. Check coil with ohmmeter. A range close to 3 to 4 ohms should be present at an ambient coil temperature of 70\uffffF. Replace coil.
Check coil voltage to make sure it is compatible with the voltage coming in. (If voltage is too high, this could cause the coil to burn out.) Change battery or coil to meet your requirement.
Burnt out coil caused by frictional contact (rotor strike). If so, coil will be discolored, can be cracked, burnt or epoxy can be melted. (Example 1, Example 2) Replace coil.
Clutch engages, but load will not engage. Rivets or springs broken.
Replace clutch.
Key missing. Put in key.
Armature could be warped because of heat due to slippage. This means it will pull in, but will slip when a load is supplied. Clutch should show signs of heat. (Example) Replace clutch and determine why it slipped.