Electromagnetic Clutch

These clutches use a single plate friction surface to engage the input and output members of the clutch. This style of clutch is used in applications ranging from copy machines to conveyor drives. They are the most common type of electromechanical clutches.

Other applications for these clutches could include packaging machinery, printing machinery, food processing machinery and factory automation.


  • Zero backlash armature available on some units: The armature is mounted to the hub by a special leaf spring to provide minimal backlash and no armature rattle.
  • Automatic air gap available on some units: Clutch air gap automatically adjusts as the clutch wears, allowing for a consistent air gap that maintains a consistent time to engagement.
  • Fast Response: The single friction plate design allows for a very fast response in high cycle applications.
  • Smooth, quiet operation: Whether automatic air gap or zero backlash is chosen, clutch armatures engage smoothly, eliminating chattering noise, helping in sustaining quieter operation.


Electromechanical clutches operate via an electric actuation, but transmit torque mechanically. When the clutch is required to actuate, voltage/current is applied to the clutch coil. The coil becomes an electromagnet and produces magnetic lines of flux. This flux is then transferred through the small air gap between the field and the rotor. The rotor portion of the clutch becomes magnetized and sets up a magnetic loop that attracts the armature. The armature is pulled against the rotor and a frictional force is applied at contact. Within a relatively short time the load is accelerated to match the speed of the rotor, thereby engaging the armature and the output hub of the clutch. In most instances, the rotor is constantly rotating with the input all the time.


When current/voltage is removed from the clutch, the armature is free to turn with the shaft. In most designs, springs hold the armature away from the rotor surface when power is released, creating a small air gap.


Cycling is achieved by turning the voltage/current to the coil on and off. Slippage should occur only during acceleration. When the clutch is fully engaged, there is no relative slip (if the clutch is sized properly). Torque transfer is 100% efficient.