What does dU/dt mean in high voltage test AC?

With this technology, very small discharge currents can be quickly detected even when a full discharge has not yet occurred.

This technique is ideal for laboratory tests on winding wire, for example. Winding wires are often subjected to extreme mechanical stress before they deform. This can cause hairline cracks in the insulation.

For quality testing, we supply high-voltage test systems with the option of testing in a ball or water bath.

The high-voltage test is usually performed with a continuously increasing test voltage until the desired maximum test voltage is reached.

As soon as the first signs of insulation damage become visible, this is detected by the test device and the high voltage is switched off. The dU/dt evaluation is ideally suited for this purpose.

The figure above shows the moment when the voltage curve is no longer sinusoidal. This is caused by a weak spot in the insulation of the winding wire. The dU/dt evaluation detects this and immediately switches off the high voltage.

Incidentally, this kind of testing in a ball bath with very small metal balls or alternatively in a water bath is also applied to insulating gloves or plastic-insulated power tools, such as VDE screwdrivers.

We supply not only the high-voltage tester, but also the complete test equipment, including water or ball bath, as well as the necessary test cage for mandatory protection.