How to use a simple method to accurately determine whether the secondary side of the current transformer is open?

(1) On the power distribution panel, the two-phase current meter in the three-phase indicates normal, and the other phase indicates that the meter has a jitter phenomenon or a zero indication, then the secondary circuit of the current transformer of the phase has an open circuit.

(2) In the case of no power failure (under the normal load state of the primary side line), measure the voltage of the secondary circuit of the transformer with a peak voltmeter or a high internal resistance voltmeter (multimeter) (two terminals of the ammeter or relay) At). There is no open circuit on the secondary side of the transformer, and the voltage value is small (3V or less). If the measured voltage is high, it can be determined that the transformer has an open circuit. Immediately check whether all electrical connection points in the secondary circuit are loose or false.
(3) If the secondary side of the current transformer is open, the core flux is highly saturated, which will inevitably produce noise and heat. You can cut off the power supply first, disassemble the power distribution board shield, and touch the surface of the iron core to identify it.