Motor phase loss protector simple circuit

PESD1CAN electrostatic protection SOT23-3 24V two-way

The circuit operation principle of the device is shown in the figure above. The LSE devices are serially connected in the A, B, and C phases. When the three-phase power line is working normally, the 4 feet of the LSE output a high level. At this time, the relays J1, J2, and J3 are all in the pull-in state, so that the three-phase AC contactor CJ is attracted, and the contacts CJ1 and CJ2 thereof. CJ3 self-protection, motor M will work normally. If any one of the A, B, and C three-phase power supplies is disconnected, the one or two pins of one of the LSEs will be disconnected, and the four pins on the corresponding LSE device will be turned low. Will be released. Because its contacts j1, j2, j3 are in the logic relationship with the gate in the circuit of CJ, as long as any one of the contacts is disconnected, CJ will be discharged and the CJ1, CJ2 and CJ3 contacts will be completely eliminated. Disconnect and protect the motor M. In addition, the circuit is also equipped with a 12V DC power supply to ensure that the circuit is safe.