Braking system for high speed and power rotating machinery

A braking system for a high speed, high load rotor operating in a vacuum and suspended by a magnetic field such as in a flywheel energy storage device includes a pair of calipers disposed on opposed sides of the rotor for actuating a pair of annular friction discs into engagement with opposed sides of the rotor. Each caliper includes a mounting ring on its outer edge and an inner shallow annular groove in which it disposed one of the friction discs. A circulating fluid under pressure is directed into each annular groove for urging each friction disc into engagement with one of the opposed surfaces of the rotor for safely bringing the rotor to a stop such as in an emergency. The circulating fluid removes the heat generated by the braking action, while the controlled pressure applied by the discs also controls the position of the rotor when static such as during initialization.