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 disengage" at 9:55

Potential Problem Possible Reason Solution
Voltage not releasing. Faulty switch. Replace switch.
Rotor and armature locked together. The clutch has been severely galled and has locked up. (Galling is the condition whereby a piece of metal is trapped between the armature and the rotor and melts due to high pressure and heat, spot welding the surfaces together.) If rotor and armature cannot be separated, replace the clutch. If they do separate, follow burnishing procedure.
Pulley bearing locked. Bearing lost grease due to seal problem, temperature or water contamination.
Replace clutch.
Brake plate clamped down to tightly. If the brake nuts are screwed down too tight, the armature will be pressed against the rotor all the time. This should be evident by discoloration of the brake shroud plate. If you leave it around long enough the brake shroud and the clutch will be destroyed. (Example) Loosen brake nuts and reset air gap. If clutch is destroyed, replace clutch.