When the transformer DC resistance tester is in normal operation, it will emit a continuous and uniform "humming" sound. If the sound produced is uneven or there are other special noises, it should be regarded as abnormal operation of the transformer and can be searched according to the different sounds. If there is a fault, deal with it in time. There are mainly the following faults:

When the power grid is over-voltage, single-phase grounding or electromagnetic resonance occurs in the power grid, the sound of the transformer is sharper than usual. When this happens, a comprehensive judgment can be made based on the instructions of the voltmeter.

When the transformer is overloaded, the load changes greatly, and due to the effect of harmonics, the transformer DC resistance tester has an intermittent sound of "wow" or "cackling" instantly, and the pointer of the monitoring and measuring instrument swings, and the pitch is high and the volume is loud.

If the transformer clamps or screws are loose, the sound is louder than usual and there are obvious noises, but the current and voltage are not obviously abnormal, it may be that the internal clamps or the screws that compress the iron core are loose, causing the silicon steel sheet to vibrate.

Partial discharge of the transformer. If the drop-out fuse or tap switch of the transformer is in poor contact, there will be a "squeaking" discharge sound; if the transformer bushing is dirty, the surface enamel is peeled off or there are cracks, you can hear " "Hissing" sound; if the internal partial discharge of the transformer or the electrical connection is poor, a "creak" or "crack" sound will be emitted, and this sound will vary with the distance from the fault. At this time, the transformer should be deactivated immediately Detection.