555 circuit diagram of electrical equipment overload and phase failure protection device

SR05 SOT143 package 5V ESD electrostatic protection

As shown in the figure, the electrical equipment overload and phase failure protection circuit. The device consists of a +12V, +5V DC regulated power supply, an AC transformer, a voltage comparator, a blocking timer, a relay control circuit, and a phase loss protection circuit. The DC regulated power supply provides DC voltage to the entire circuit.

The AC transformer LH proportionally couples the current flowing in the three phases, and is rectified and filtered by D1C1, D2C2, and D3C3, and then applied to the voltage comparators (IC1, DW1, DW5, and R7) and the phase-cut protection circuit (IC4, IC5, IC6).
A phase loss protection circuit composed of IC4 (CD4070), IC5 (7402), IC6 (CD4013), etc. is used to detect and judge the presence or absence of three-phase current. If there is a phase failure phase, IC3 is set and the relay J is sucked. Then, disconnect the power of the device for phase failure protection.