Uses for Hipot Testers??  (I am in dangerous territory) - Page 1
Forum section: electronics / testgear

author: watchmaker
author_rank: Unknown
timestamp: May 24, 2024, 01:05:35 pm
content: I bought a Quadtech Sentry 30 for $100 from eBay. I wanted a source for variable AC voltages over 120. I did find the manual for this specific unit and have read it with care.OK. So putting everything on continuous with continuity check off, I have my AC voltage source (as well as DC hi volts). I like that the danger indicator flashes as a reminder. High quality insulation leads with good cover boots.I know this is intended for product safety testing. What other uses can it serve? Can it be used to test capacitor withstanding voltages for example?It has a calibration sticker good until the end of May 2024.I am watching manufacturer videos on its proper and safe use. Yes, I KNOW this is not intended for people like me. What precautions do you follow?Thanks,Dewey

author: HKJ
author_rank: Super Contributor
timestamp: May 24, 2024, 04:12:09 pm
content: I do not want to get roasted by high voltage, on my HiPot tester there is a connection for a external safety interlock. I connected that to a box with two momentary switches on it. This means the only way to turn the high voltage on and keep it on, is when I press and hold both switches on the box (Mounted so it requires two hands).This means even if I make a silly mistake, it is very unlikely that I get roasted.I only uses mine for product safety testing, but it would also work for capacitors and destroy them if they cannot handle the voltage.

author: Gyro
author_rank: Super Contributor
timestamp: May 24, 2024, 06:13:20 pm
content: The Sentry 30 DC testing capability can potentially give you some nasty surprises. On AC test the current is limited to a non-lethal (but still very unpleasant) 7.5mA, but on DC test the current is much more determined by what you connect. It has internal discharge of loads on trip or turn off, the trouble comes if you use a loose probe and it disconnects before this happens. Even transformer inter-winding capacitance can give you a belt and capacitors will become extremely nasty. Make sure your connections are secure.Capacitor withstand testing is certainly possible, I don't know whether the meters are sensitive enough to detect the onset of corona discharge (a cause of failure in high voltage film caps that have voids in the winding (some testers actually include a speaker). Don't confuse this with breakdown testing though, which is inevitably fatal to all but X caps (which will just be unhappy and lose value).I have a Hunting Hivolt 0-10kV, 1uA /10uA / 100uA trip tester that I use for withstand and insulation leakage testing (DC).P.S.Although 1kV certainly needs to be treated with respect, it isn'ttoofar into dangerous territory. For instance it is the same limit as most electricians' insulation testers can put out, and it shouldn't be able to break down even an X2 cap.EDIT: Scratch that, the spec is a bit confusing, it's 1kV forInsulation resistancetesting but 6kV for Hipot! The breakdown trip time is less than 10us which is a good deal faster than an RCD though.

author: HKJ
author_rank: Super Contributor
timestamp: May 24, 2024, 06:44:34 pm
content: Quote from: Gyro on May 24, 2024, 06:13:20 pmOk, my tester is a bit more lethal than that, it can do 100mA at 5KV AC (GPT-9903A), but I do not want to test how much I can withstand! (I have done that a few times and I definitely prefer not to do it anymore).

author: Gyro
author_rank: Super Contributor
timestamp: May 24, 2024, 07:03:04 pm
content: Quote from: HKJ on May 24, 2024, 06:44:34 pmAh yes. 500VA and >200mA short circuit current is definitely in 'I'd rather be somewhere (anywhere) else' territory! I can't immediately see a trip time value on the spec sheet either.