The three-phase motor adopts a commutation circuit with automatic stop by proximity switch.

In the circuit shown in the figure, 1SQ and 2SQ are new contactless transistor proximity switches, and STF and STR are forward and reverse push button switches respectively. When STF is pressed, KMF is attracted and the motor rotates forward. At a certain limited position, the metal piece on the machine is close to 1SQ, and its internal contacts are disconnected, causing the KMF coil to lose power and the motor to stop. Compared with mechanical limit switches, contactless transistor proximity switches have better performance, more reliability, and longer service life.