Constant Voltage Transformer Failure 1

[Luke2233]

Recently had a CVT failure in a 40 year old system. 115VAC supply with 100VAC load floating. When it failed the load voltage was still correct, but we had 550 volts to ground. What we found was one side of the capacitor in the CVT was grounded. The question I have is how was it able to generate a voltage 5 times the source value in the ground

 

[Skogsgurra]

The secondary of a CVT contains a resonant circuit that drives magnetization in the core into saturation so the output voltage is kept more or less constant. That means that the voltage across the capacitor is several times higher than the output voltage. If your capacitor is grounded, then you can measure the high capacitor voltage between one of the phases and ground.

Gunnar Englund

http://www.gke.org

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