Valcor Engineering Corporation

Motion Control Permanent Magnet Failsafe


The PMFS-series electrically off clutches and brakes are designed to control the motion of a rotating motor shaft. The clutch engages the motor shaft and provides power to the drive train. The clutch is activated electrically; when power is turned off or interrupted, a powerful permanent magnet disengages the clutch from the rotating shaft. The brake stops a rotating shaft. The brake is held off electrically, a field coil creating the magnetic holding force. When power is shut off or interrupted, a powerful permanent magnet causes the brake to activate, stopping the shaft rotation. Permanent magnet clutches and brakes have a larger torque to weight ratio than comparable spring-set devices.


Rotating shaft clutches and brakes provide rotary motion control on a space craft, launch vehicle, aircraft, land-based vehicle or commercial and industrial equipment.

  • Factory Automation
  • Spacecraft and Aircraft Systems
  • Business Machines
  • Printing equipment including 3D printer, copiers, and printing presses
  • Packaging equipment
  • Conveyor Systems

Design Features and Benefits

  • Self-adjusting; no need for readjustments
  • 24 VDC standard; other voltages available
  • Reliable performance over wide temperature range -65° to 350° F
  • Mil spec models available
  • Stationary field coil – no slip rings or brushes
  • Vibration-Proof epoxy resin encapsulated field coil
  • 30% faster response compared to spring-set models
  • Fully customizable for your application