Patent ID: 6661144
Filing Date: 2003-12-09
Classification: F04D,H02K

Abstract:
An electromotive drive, with at least one fan wheel (2) which can be driven by an electric motor (1) and is supported freely rotatably by a motor casing (5) of the electric motor (1) via a bearing (4, 4â€²),wherein an electromagnetic slip coupling dependent on the motor speed is arranged between a motor shaft (3) and the freely rotatably mounted fan wheel, wherein an electromagnetic speed limiting and governing device which limits the delivery of cooling air to the required quantity of cooling air is provided between the motor shaft (3) and the fan wheel (2), wherein the fan wheel speed decreases in relation to the motor speed, when the motor speed exceeds a predetermined level so that the slip coupling becomes increasingly ineffective to engage the fan wheel, and increases again, when the motor speed drops below the predetermined level and the slip coupling increasingly re-engages the fan wheel, and wherein the motor shaft (3) bears permanent magnets (6), and a hub (7) of the fan wheel (2) has an electrically conductive part or the fan wheel is provided with permanent magnets and the motor shaft is provided with an electrically conductive part.