Abstract: A variable speed drive has an asynchronous motor whose output shaft carries a flywheel which is juxtaposed axially with a ferromagnetic disc movable on a spline of an output shaft journaled in a common housing for the flywheel, the disc and at least one electromagnetic coil surrounding the output shaft, located within the parameter of the disc and energizable to control the relative engagement of the disc with a brake ring on the housing and a clutch ring on the flywheel. Vanes on opposite sides of the flywheel induce air to flow axially into the housing through the disc and radially out of the housing for cooling.