Double interlock control circuit of three-phase asynchronous motor

The forward and reverse double interlock control circuit shown is based on the control circuit in Figure 4-4 and adds a mechanical interlock link of a composite button
. The advantage of this circuit is: if you want to reverse the forward running motor , you don't have to press the stop button SB1 first, just press the reverse
start button SB3 directly; of course, the same is true from reverse running to forward running. This circuit has electrical and mechanical dual interlocking functions,
which not only improves the reliability of control, but also can realize forward-stop-reverse-stop control, and forward-reverse-stop
control.