Fault phenomenon: The IF power supply starts normally. When the power is adjusted to a certain value, the overcurrent protection is stopped. The overcurrent action is not obvious. It is still far from the set value when observing the overcurrent action.
Fault analysis: Judging by the fault phenomenon may be caused by interference signals.
Solution: Start the adjustment to the overcurrent threshold. Observe that there is an indication on the panel of the inlet cabinet. The shutdown check reveals that the inside of the header is open and the new one is normal.
Case summary: The principle is very simple. The device saves the material. The primary current signal is taken out in series with the transformer after being taken out by the current transformer. Once the ammeter is open, it is equal to the open current of the current transformer, thus generating a very high induced voltage. The signal is applied to the transformer (5A/0, 1A), which is coupled to the main control board, causing an overcurrent fault.
