No error when AC1 of.0 kV is applied to non-defective products.
A AC1 of.0kV was applied to a non-defective stator from a voltage-proof meter, and the wave forms of current (green wire) and voltage (blue wire) were observed. The memory high coder MR6000 can store data for 2.5 seconds (digital recording) even when the sampling speed is set to 200MS/S (=5 ns) at the maximum. When the recorded waveform for 2.5 seconds was checked, the current waveform did not appear to be partial discharge pulses.
Although the peak-to-peak value of the current waveform is a minute signal of about 1mA, the current-probe CT6711 can be output at 10mV / mA, so it was very useful for observing such leakage currents. However, since the DC drifting is severe (in fact, 0A position is shifted in the diagram on the right), it is desirable for the Memory Hicoder to set "AC-Coupling".
Partial-discharge pulsed is detected when AC1 of.5kV is applied to a non-defective product.
When the applied voltage from the withstanding voltage meter was increased gradually, partial discharge pulses appeared in the current waveform of the good stator at about AC1 of.5kV. However, in 2.5 seconds, it appears only in the area shown on the right. In other words, PDIV is 1.5kV.
For pseudo-defective products, AC1of.0kV Partial discharge pulse detected when is applied.
Next, voltage was applied to the pseudo-defective product from AC1 of.0kV. However, partial discharge pulses appeared suddenly as shown in the right-hand figure. That is to say, PDIV was 1.0kV or less, and there was obviously a difference from the non-defective product.