Just got my new 0-15 kv dc hi-pot tester from Tom Rauch, W8JI at CTR engineering. It's a thing of beauty. Beautifully constructed.
Received mine over the weekend. Nicely constructed and a worthy companion to a 6 KV Megger model I've been using.
In addition, an inexpensive Eisco microammeter can be used with either device. It's a moving coil movement that measures from -20 uA to +100 uA. Zero is centered about a quarter of full scale.
Paul, W9AC
Tom indicated to use a 100k to 500k resistor in series with the hot side, when hi-pot testing stuff like grid to cathode on oxide tubes. I'm suggesting that may also be a good idea when testing vac variable caps. However, I'm not clear on what type of resistor should be used for this application. Does it need to be HV rated ? Can the resistor be in series with the return leg ?
I was testing a ton of stuff with it. ( Fluke 87 DVM in return lead, on it's 0-4000 ua scale) and when testing a jennings 50-4000 pf vac cap ( 5 kv rated)... I noticed it showed no leakage at 5 kv. But just a TINY bit above 5 kv..and poof, it arced the plates. It went from 0 ua, to aprx 7 ua to ARC. ( I had NO resistor in series with either leg) On some other items, the leakage current just keeps on increasing. On these other items, HV can be increased till leakage can be 50 ua. Then on my vac cap, it arcs with > 5-7 ua..... go figure.
So far, so good. But it really requires a ua meter in the return leg at all times.