The invention relates to a circuit (1) for protecting against overload of an electric motor (2), more particularly an electrically powered air blower for a vehicle, with the purpose of providing sufficient and appropriate protection even when several electric motors are connected in series. Said circuit is provided with at least one switching element (6) for controlling two series connected electric motors (2) independent of revolutions, in which a switch element (14) configured as a make contact element (12) is connected in parallel to the electric motor (2), said switch element causing short circuiting of the corresponding electric motor (2) in case of overheating.