PHASE IDENTIFICATION DEVICE FOR THREE-PHASE ALTERNATING CURRENT POWER SUPPLY

摘要

A phase identification device for a three-phase alternating current power supply comprises a state selector (10) connected to a positive electrode of a voltage output by a load and controlling a circuit to be switched on and switched off according to presetting, an isolation unit (12), a power supply (14) and a signal processing unit (16). The isolation unit (12) comprises two input ends and two output ends; the first input end is connected to a negative electrode of the voltage output by the load, and the second input end is connected to the state selector (10); the first output end is connected to one end of a pull-up resistor and the signal processing unit (16), and the second output end is grounded; a non-grounding signal is isolated by the isolation unit (12); the power supply (14) is connected to the other end of the pull-up resistor; and the signal processing unit (16) is connected to the first output end of the isolation unit (12) and determines a phase of the load according to a high level signal or a low level signal output by the isolation unit (12). The device is simple in design, low in cost and easy to implement and can be applied to all occasions in which the phase of the three-phase alternating current power supply is required to be identified.