| 摘要 |
The invention relates to a circuit for controllably driving an A.C. motor which includes a voltage supply with a pulse modulation regulator followed by an intermediate smoothing circuit and an inverse rectifier. Each phase of the inverse rectifier has two controllable load switching elements in series between two supply lines with each element being bridged by a recovery diode. The voltage of the intermediate circuit is adjustable by a desired value generator and the frequency of the inverse rectifier is adapted to follow the existing value of the voltage of the intermediate circuit. At least one phase of the inverse rectifier is associated with a braking circuit having a brake resistor between one phase connection and a brake connection which is disposed between two series connected brake switching elements disposed between the supply lines. Mounting blocks each with a load switching element and a recovery diode are mounted on a common mounting surface with connections which are disposed on the side opposite to the mounting surface and are directly interconnected by supply line rails and phase connection rails. The two brake switching elements are likewise arranged in a block which is mounted on the mounting surface with connections to the supply line rails and to a phase connection rail.
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