Control circuit for three=phase asynchronous motor - has memory storing switching points and slows speed before shaft reaches its final point

摘要

The control circuit is for a three-phase asynchronous motor driving shafts of an industrial robot. The motor can be switched to a lower speed. This is done before the corresponding shaft reaches its final position at which the motor is switched off. A memory is provided, in which the switching off and over points are stored. The shafts have angle coders through which their position at the switching off point is detected. This position is compared with the nominal position, and in case of a difference the stored switching over point is erased and replaced by a new point.