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If space is limited and saving weight is critical, the XS Series of brakes from Warner Electric, New Hartford, Conn., are good options for reliable, statically engaged/disengaged brakes. These spring-set holding brakes are said to be the smallest on the market, with the holding performance of 1.5 to 50 N-cm of holding torque. The composite friction material used in the brakes was a key to keeping them small.
The brakes are spring-set applied and electrically released, so they remain engaged despite power failures. This makes them suitable in applications that must maintain holding force. They can also be used in low cycle-rate applications such as seat adjustments on planes or trains.
The springs that supply the holding force replace the heavier and more expensive magnets usually found in brakes. Extensive testing by Warner Electric engineers proved that the springs offer the same static torque capacity and make the brakes lighter.
The six XS brakes weigh from 30 to 100 gm, are powered by 12 or 24 V, and have external diameters that range from 22 to 33.5 mm.
Components for the brake are precisely cut and assembled with equipment that lets technicians set the air gap while mounting the housing onto the shell. Components were also optimized to fit in the small housing.