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.
Voltage is going to the clutch but the clutch will still not engage. The air gap is too large. (Example) If straight bore the air gap can be readjusted. If unit has set screw, bottom out armature hub against field then back off to 0.1 inches and re-tighten set screw. If spacers are used on straight bore reduce the width of the spacer. If it’s a taper bore clutch tap on the armature cover plate to close air gap.