One of the protection circuits to prevent short circuit when the motor is started in reverse

During the forward and reverse switching process of the motor
, an arc will be generated when the contactor contacts are disconnected. If
the reverse contactor is closed again before the arc is extinguished,
a serious short circuit accident will occur. This requires a protective circuit
to prevent phase-to-phase short circuits .     The circuit is shown in Figure 4-63. This circuit can ensure that during forward and reverse operation, the stop button must be pressed first before proceeding. This means that during the forward and reverse conversion process, the contactor contacts can be guaranteed to have sufficient arc extinguishing time, thereby effectively preventing phase short circuits . This is achieved through the interlocking of the normally closed auxiliary contacts of the forward and reverse contactors KMi and KMz .