Abstract: A control unit and method for operating a gap-type electromagnetic clutch or brake is provided which reduces audible chatter, screeching caused by belt slippage and related wear and tear on the driving and driven components. The operating winding of the clutch or brake is energized to cause the gap between an armature and rotor to close, energization of winding is then reduced to initially reduce the torque coupling between the armature and rotor and finally energization of the winding is gradually increased to full energization so as to provide a gradually increasing torque coupling between the armature and rotor.