Abstract: Electric motors, in particular geared motors, are often equipped with electromagnetically actuated mechanical brakes. In order to ensure that an excitation coil (3) can be operated with alternating-current mains supplies of various voltages, it is proposed to generate a unipolar voltage that varies over time with a certain period by means of a voltage source (2), the output voltage of which is positive and different from zero in a first time segment of this voltage period and in this first time segment has a maximal value, and in a second segment of the voltage period is zero or approaches zero. To pass an excitation current from the voltage source (2) to the excitation coil (3), a current path (15) is provided that is opened substantially at the beginning of the first time segment. The current path (15) is blocked again at a certain point within the first time segment, this point being selected such that the excitation current does not exceed a predetermined maximal value.

Abstract: An electric motor with a frequency converter for speed control purposes and in which a frequency converter casing is provided with a cooler, is characterized by an intermediate part, replacing a terminal box and receiving the connecting elements. The intermediate part allows the frequency converter casing to be fitted in a thermally decoupled manner with respect to the electric motor.