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 the following sections that deal with Noise: Noise - 11:47
Noise - armature/hub - 12:34
Noise - bearings - 13:33
Noise - rotor contact - 15:42

Potential Problem Possible Reason Solution
If clutch is able to move on the shaft. Check center bolt and washer to make sure it is tight. If it is tight, make sure that the shaft is not too long. Clutch shaft should end before the end of the clutch to allow some deflection in the center bolt and washer to keep clutch on tightly.
Retighten center bolt or change spacer or shaft length.
Noise from pulley bearing. Check if bearing feels rough. Check belt load to make sure pulley and bearings are not over loaded. Reduce belt load.
High temperature can be caused by either operating environment or due to slippage. If slippage, clutch should be discolored. Refer to slippage section for potential reasons. Reduce the heat or eliminate slippage.
Pinging or scraping noise noticed when clutch is disengaged Air gap too close.
Increase air gap.
Surface is heavily galled. Re-burnish the clutch.
Noise from field bearing. Check to see if the clutch is discolored to see if it shows signs of slippage. Refer to slippage section.
Check for damage to both the outer race and inner race of the bearing. Make sure key is not too tight forcing pressure on the inner race . In the outer race area, check for marks or damage that could have caused the clearances to close up.
(Example 1, Example 2, Example 3)
Replace clutch.
Check temperature of shaft where clutch is mounted to verify that it is under 300°. Reduce reason for the high temperature overloading on the engine.
Check torque tab or backing plate to make sure that there is freedom of movement of 1/16 of an inch axially and radially. Check to see if any marks are evident that would indicate axial forces applied.
Loosen torque tab to make sure it has freedom of movement both axially and radially.