Circuit arrangement for controlling or regulating the starting (acceleration), braking and rotation speed of a three-phase asynchronous motor

摘要

The invention relates to a circuit arrangement for controlling or regulating the starting, braking and rotation speed of a three-phase asynchronous motor, comprising a regulator whose first input is connected to a device for detecting the actual rotation speed of the motor, whose second input is connected to a device for presetting the required rotation speed, and whose output is connected to a plurality of power semiconductors, such as triacs, alternistors or thyristor pairs connected in opposition in parallel, in order, via a phase-gating controller, to control the three-phase supply fed to the motor turns from the terminals of the motor, a rotation direction reversing circuit furthermore being provided in such a manner that the assignment of at least two phases to two motor turns can be interchanged, and, in the case of at least some of the phases, the assignment to the respective motor winding taking place by the power semiconductors being turned on or turned off by means of the control and regulating arrangement. In order to achieve a construction which is as simple and compact as possible, it is provided that one phase of the terminal voltage is connected directly to one motor winding, without the interposition of power semiconductors. As a result of the reduction in the number of components achieved in this way, it is possible with particular advantage to accommodate the controller on or in the motor housing, particularly in the terminal box.