Interlock means that the two AC contactors can not be switched on separately. It is generally used in the forward and reverse power supply circuit of motor. If the two AC contactors are switched on separately, the short circuit fault in each phase of switching power supply will occur. The wiring method of electrical equipment interlock is: the normally closed contact of KM1 AC contactor is connected in series with the electromagnetic coil circuit of km2 AC contactor, and the normally closed contact of km2 AC contactor is connected in series with the electromagnetic coil circuit of KM1 AC contactor. However, if an AC contactor contacts arc welding, electrical equipment interlock is invalid. Therefore, the AC contactor with mechanical equipment interlocking must be applied in the site with strict regulations.

The two AC contactors intervene the storage capacity of each auxiliary normally closed point in the control circuit of the other party and lock each other, so that the two AC contactors can not be switched on.

This circuit is very simple. The basic principle is to ensure that the motor can not be connected when the motor is turning forward, and the motor can not be connected when the motor is turning forward. Otherwise, if the AC contactor is switched on, the three-phase AC will have a short circuit fault in the lower hole of the AC contactor. Therefore, it is necessary to add locking in the circuit. In addition, whether the motor is turning forward or not, it can be connected anytime and anywhere To terminate the operation of the motor, the stop button should be connected in series, and the start button should be connected in series.

The two AC contactors are KM1 and km2 respectively. If the auxiliary normally closed contact of KM1 AC contactor is connected in series with the control circuit of km2, and the auxiliary normally closed contact of km2 AC contactor is connected in series with the control circuit of KM1, it will have the interlocking effect. When all one AC contactor is closed, the control circuit of the two outer AC contactors will be broken, and the current will not form a loop It's not easy to pull in.