The invention concerns an electric motor comprising a pressure-equalizing device which consists of a BTFE membrane disposed in a connection duct between the interior of the electric motor and the ambient air. The membrane (24) is disposed in the end cover (3) of the electric motor (1). Since the end cover (3) is made of plastics material, the membrane (24) can be injection moulded when the end cover (3) is manufactured such that the membrane (24) is permanently attached to the end cover (3). However other types of attachment are also possible. A particularly suitable location for attaching the membrane (24) is a peripheral collar (21) by means of which the housing (2) is centred relative to the motor shaft (5). The connection duct is in the form of a slit (22) on the exterior of the collar (26). The application also describes further types of attachment.
