ENDURA       (hysteresis & eddy-current clutches)



The hysteresis unit is comprised of two permanent magnet assemblies which face each other. Each assembly consists of a ring of magnets of alternating magnetic polarity. Between them is a rotating disc which is attached to an output shaft.

A small air gap separates the disc and magnet assemblies. There are no moving parts in contact to produce torque. Instead, the alternating magnetic field impedes the disc's rotation, thereby producing torque. No power is required since permanent magnets are used to create the magnetic field.

The eddy-current unit has similar construction as the hysteresis unit. In this case torque is produced only when the disc is rotated. Torque increases linearly with slip speed and is zero at zero slip speed.

With no friction surfaces, torque is accurate and repeatable regardless of slip speed. Torque is not affected by slip speed. No slip/stick makes them the most accurate devices available even at slips speeds to zero rpm. Life is virtually unlimited for precise tensioning or torque limiting even in 24 hour/day service. Torque is infinitely adjustable by rotating the knurled knurled end of the unit. They can be mounted horizontally or vertically with no ill effects.

They are ideal for constant slip applications where friction or magnetic particle brakes would wear out, provide inconsistent torque, or contaminate the environment. Slip speeds are limited only by the unit's heat dissipation capacity.
Brake life is not derated as torque or slip speeds increase unlike friction devices which must reduce allowable torque or slip speed to improve life ratings. There is no break-in period and torque will not change for the life of the clutch.


High quality materials are used throughout. Including:


   * High quality ABEC bearings.

   * Precision ground, alloy steel shaft.

   * Temperature stabilized rare earth magnets.


Custom designs including special shafts / mounting / torque / stainless steel construction / metric dimensions.

Accurate, Repeatable Torque
 * Torque produced only by a magnetic field.
 * Accuracy: +/- 5%.
 * Smallest torque variation, static to slipping.
 * Infinite adjustability by rotating knurled end of unit.
High Torque Per Size
 * Rare earth magnets for 3-5X more torque than other
   hysteresis clutches.
 * Improved torque / inertia ratio allows faster start-ups.
Maintenance Free
 * No friction surfaces to wear or adjust.
 * Virtually unlimited life, other than bearing wear.
No Power Required
 * Permanent magnets create the magnetic field.
Custom Designs Welcome
 * Special shaft designs, mounting, or torque available.
 * Stainless steel construction or metric dimensions.

          * Filament unwind / braiding
          * Dynamometer motor testing

            * Web or wire tensioning
            * Indexing / cycling

    * Torque overload protect / soft starts
    * Filter torsional vibration

Unwind Brake
Constant Tension Pinch Roll
Shaft to Shaft Coupling
With the eddy-current model, vary slip speed to
adjust torque during operation and compensate
for increase in spool diameter
Use the brake in a pinch-roll setup
to maintain constant web tension.
An adapter rotates the clutch body for the input.
The clutch shaft is the output.
Clutch adapters are available.