Recommendation needed - setup for testing of power supplies - Page 1
Forum section: electronics / beginners

author: bitman
author_rank: Unknown
timestamp: July 10, 2020, 12:11:48 am
content: I want to setup a relatively easy but also safe setup to test 120v -> 24/12/5/3.3v PSUs. I have an isolator but I would like something on the bench to avoid having the live wires so exposed. I was thinking of just putting something together - and while I think about the best way to do that, I wondered if there are existing setups - so at the very least I can compare what I want to do with what others do, and perhaps what a professional setup is.I want at the very least a switch right by the unit I'm testing to turn power on/off. And relatively flexible wires from a connector on the bench (that I would like to put in a protected enclosure) so it's easy to turn the unit on/off. Since the whole point of this is that I want to be able to test load limits and ensuring output is correct, noise levels etc. I need to be able to easy access the module I'm testing - not while power is on of course, so perhaps something that will not turn power on until a cover is over the unit being tested. Not sure yet - still thinking.If such a thing already exists I would love to know about it.

author: ledtester
author_rank: Super Contributor
timestamp: July 10, 2020, 12:46:56 am
content: > so perhaps something that will not turn power on until a cover is over the unit being tested.This is a nice safe AC mains connector:http://www.farnell.com/datasheets/2829163.pdfAn overview:https://youtu.be/_DTmL73th7Y

author: Ian.M
author_rank: Super Contributor
timestamp: July 10, 2020, 01:02:54 am
content: I also recommend the Cliff Quicktest CT1https://www.cliffuk.co.uk/products/tools/quicktest.htmIt provides a fused safety disconnect and quick connection of individual wires to your mains supply. You'll want the CL1857 North American colour coded version, and also order a pack of assorted BS1362 fuses as spares for it as those are a different size to the usual American and metric fuses.Ledtester already posted the Youtube link to Big Clive reviewing the 240V version. Watch it!Protecting the whole input side of the PSU under test against casual contact while allowing access to the low voltage side is a lot more difficult unless you only work on a limited number of models you can make model specific plastic guards for.

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 10, 2020, 12:49:40 pm
content: I use such a simple decision (on a attached photo). The whole box is connected to 400VA isolating transformer.I can use either wall socket or connector (depends on a device degree of readiness). Now I'm thinking about to add a Chinese panel LCD Ampere-Volt-Watt-meter in the center of that box (there is free space).

author: bitman
author_rank: Unknown
timestamp: July 10, 2020, 09:46:15 pm
content: Quote from: Vovk_Z on July 10, 2020, 12:49:40 pmDid you design this box? My current plan is an acrylic cover than turns the power on when I close the box - meaning I have to connect everything including probes and then close the lid. It's actually the final wire and what I probe I want to mainly protect, as it's what I think I'm most likely to hit by mistake.And I just happened to have a Chinese LCD Amp/volt meter lying around (for AC) which I just added to the prototypeMy prototype works with two simple contact relays (3D printer guys call them "end-stops") that controls power, and two LEDs - one that shows power is being supplied to the "base" and another that shows power is being provided to what I'm testing. Nothing fancy.About the fuse - I was betting on the fuse in the isolating transformer unit to cover me. I don't expect to ever get to 7amps that it's set for, so it's mainly there to deal with short-circuits. I guess I could use a smaller fuse on the board? Not sure if that would make things better?

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 11, 2020, 02:49:28 am
content: My box has DP-switch (open/close both wires), then fuse - I change fuse for actual Device Under Test rated current (from 0.1 A to 10 A). Then it goes a series incandescence lamp (as a current limiter), but I added I-0-II switch to chose between lamp (or external shunt) and two constant shunts - 1 Ohm and 10 Ohms resistors (to measure current value or to see a current form with oscilloscope. And then goes output in two parallel variants - for mains fork and for wires. As you can see two-wire connectors have a translusive protective cover. That is all.Thanks to China I can add now a panel meter (AC multimeter) too.