Power Designs 2K100P high voltage calibrated power source - Page 1
Forum section: electronics / general

author: Cyclotron
author_rank: Unknown
timestamp: January 08, 2025, 06:02:26 pm
content: I needed something to generate high voltage for testing. I was going to build something when I found this 2k100P on eBay for cheap.The only problem I've found is the missing knob. My equipment (not traceably calibrated) indicates it is dead on its spec sheet.I'm posting pictures in case someone is interested and recording the boards in a working state in case someone needs them.

author: TimFox
author_rank: Super Contributor
timestamp: January 08, 2025, 06:32:07 pm
content: What connector is used for the high voltage output?

author: Cyclotron
author_rank: Unknown
timestamp: January 08, 2025, 06:44:18 pm
content: Quote from: TimFox on January 08, 2025, 06:32:07 pmThe connectors are SHVhttps://en.wikipedia.org/wiki/SHV_connector#:~:text=SHV%20connectors%20are%20used%20in,20%20kV)%20are%20also%20available.Seems I didn't include a pic of the rear. I'll update with one.

author: TimFox
author_rank: Super Contributor
timestamp: January 08, 2025, 06:48:00 pm
content: Back in grad school, where we used HV for PMTs, we often replaced “MHV” connectors on commercial power supplies with “SHV” (same mounting hole).Too often, new students would insist on un-natural mating of BNC and MHV.The only HV cables built by the electronics shop in the research building used SHV.

author: Cyclotron
author_rank: Unknown
timestamp: January 08, 2025, 06:53:00 pm
content: Indeed, I have a conundrum. I really only need the device in the 500-1k range. It is simply a test for those scales on meters I restore and test. Considering the upper range, I am contemplating how to build a useful but not deadly test harness. I am leaning towards disabling the ability to set the output higher than 1k internal to the unit but make sure it's easily reversible in case a need arises.

author: TimFox
author_rank: Super Contributor
timestamp: January 08, 2025, 06:59:37 pm
content: Can you just use a length of RG-59/U solid PE cable, with maybe 3 to 4 inches of shield stripped back, into two “safe” banana plugs, with heat-shrink tubing on the braid?(Again in grad school, I once used RG-59A cable with foam PE dielectric: bad choice that broke down somewhere around 2 kV.)

author: Cyclotron
author_rank: Unknown
timestamp: January 08, 2025, 07:05:14 pm
content: I considered a BNC termination, but that keeps the contacts too close, even at 1k, for my liking.As you suggest, a banana jack panel made up is where I'm headed. It makes a lot of sense as I can maintain separation, and it's the most straightforward connector to suit my purposes.Thanks!

author: garrettm
author_rank: Frequent Contributor
timestamp: January 09, 2025, 09:08:28 am
content: I made my own SHV to isolated 4mm banana cables for my HP 6110A 3kV PSU. I used some Raychem Y heatshrink boots to make them look a little more professional.While huge, I really like the build quality of this Power Designs unit. The WW resistors looks excellent (and very expensive)! Can you see the temperature coefficient printed on them? The HP unit I have used 5ppm/C parts.

author: garrettm
author_rank: Frequent Contributor
timestamp: January 09, 2025, 09:24:25 am
content: Here are some photos of another unit I restored. It had some bad resistors in the switch deck, from oxidized / misaligned switch contacts that caused arcing. Re-aligning the switch blade so it cleanly did make-before-break switching and some baking soda with a toothbrush, a good rinse, and a tiny amount of deoxit carefully added to the contacts fixed this issue. Replacement resistors were pretty damn expensive though.

author: TimFox
author_rank: Super Contributor
timestamp: January 09, 2025, 03:22:05 pm
content: Quote from: garrettm on January 09, 2025, 09:08:28 amAgain, back in grad school, we had two -hp- 6110A 3 kV supplies in the main rack for electron multiplier power.It was easy to swap SHV panel connectors for the MHV connectors supplied by -hp-.

author: Cyclotron
author_rank: Unknown
timestamp: January 09, 2025, 05:48:58 pm
content: Quote from: garrettm on January 09, 2025, 09:08:28 amNothing that I can find written on them, but from the specs, I can find they are +/- 5ppm/C.You weren't joking about the expense. 3 of these resistors are what I paid for the whole thing.I can't wait to tell a buddy this when he asks how much I spent on it: "I bought it for 3 resistors"

author: guenthert
author_rank: Frequent Contributor
timestamp: January 12, 2025, 12:22:14 pm
content: Quote from: Cyclotron on January 08, 2025, 06:53:00 pmIt's not so much the 1kV you need to worry about (well, 1.5kV might fry the DUT), but the potentially very hurtful (lethal, if you're unlucky) 100mA at high voltage. It's clearly an old instrument, else it would be plastered with warning labels. When modifying the source, you might want to consider substituting the current limiter as well. Wonder what a calibrated high voltage 100+W source would be needed for. Piezo driver?I do like, that it's finally an instrument which goes all the way to 11. ;-)

author: Cyclotron
author_rank: Unknown
timestamp: January 13, 2025, 12:00:59 am
content: Quote from: guenthert on January 12, 2025, 12:22:14 pmI, too, was very tickled that it went to 11.I have no idea what it was used for during its life, though I recall the seller being someone who disposes of university gear.I have several Power Designs bits and bobs and really like what they put out back in the day, so that was a factor in purchasing it. I need a reliable 500-1k DC voltage source to test (not calibrate) the equipment I've repaired (mostly DMMs) to be sure they can take measurements. I was going to build a source with a transformer I sourced from a microwave that was being disposed of. This was a huge shortcut for that. And the last reason is it was dirt cheap.

author: lowimpedance
author_rank: Super Contributor
timestamp: January 13, 2025, 02:32:16 am
content: Reminiscent of old Fluke 412b (etc) HV supplies. Those used Valves though.Don't see much posted here about these types of supplies, thanks for the pics.Perhaps you could figure out a way to incorporate the interlock into your test fixture for added safety .

author: garrettm
author_rank: Frequent Contributor
timestamp: January 13, 2025, 07:27:14 am
content: HV supplies are commonly used with charge line pulsers, pulse forming networks (PFN) for radar systems, various vacuum tubes (photo-multiplier tubes, x-ray sources, etc.), electrostatic effects for micro/molecular biology research (e.g., electrophoresis), electro-optic modulators and so on. Lots of cool stuff really. The "water bridge" experiment is really neat to see.An interlock would be a good idea. I had an old 4kV electrophoresis PSU that used an open frame 250V DPST contactor with both contacts connected in series to safely open the circuit (contacts were each spaced 0.25in apart when open). But a cascode using HV IGBTs or SiC MOSFETs would work too. An SCR crowbar might not be a bad idea either (as a fast acting kill switch). Really just depends on what you have and are comfortable working with. The big issue with HV is continuous arcing due to metal vapor sustaining the arc. A home-brew HF current transformer could be used to detect oscillations and trigger a crowbar or another mechanism to kill the arc and avoid accidentally radiating EMI.

author: Cyclotron
author_rank: Unknown
timestamp: January 14, 2025, 01:06:44 am
content: The unit has an "interlock" function. The two pins on the back are shorted per the note on the back panel as its not in use.I suppose I could incorporate that into a covered "ARM" switch on an output panel.I don't know why but I think having an arm switch would be cool.Note that I am in my 50s and not grown up yet....