Brake Motors

A brake motor has an electromagnetic brake mounted on the non-drive end. When the motor is energised, the coil releases the brake; when power is cut, springs press the friction disc and stop and hold the shaft. This fail-safe action makes it suitable for hoists, conveyors and positioning drives where the load must not coast.

In a brake motor the brake is built into the motor housing, so the package is compact and the brake is matched to the motor. An external brake, such as a drum or thruster brake on a coupling, is used for larger torque or where the brake must act on the load side of a gearbox. Selection depends on torque and mounting.

Calculate the load torque at the brake shaft, add a safety factor appropriate to the application, and also check that the brake can absorb the kinetic energy of the load inertia during stopping. For lifting duty, applicable crane or lift standards may set the minimum factor. Provide the load and speed data and let the supplier confirm the brake size.

Yes, if the whole assembly, including the brake, is built and certified for the area, as in a flameproof motor with brake. A standard brake motor must not be used in a classified zone. State the zone, gas group and temperature class when you ask for a quotation, and confirm the certificate with a qualified engineer.

They can, but the brake coil should be supplied separately from the drive output, not from the motor terminals, because the output is a variable-voltage, variable-frequency supply. The control sequence must also close the brake only after the drive has brought the load to a stop. Check the drive and brake manuals for the recommended sequence.