Inexpensive low current DC current clamp - Page 1
Forum section: electronics / testgear

author: BeBuLamar
author_rank: Super Contributor
timestamp: October 28, 2024, 02:56:46 pm
content: I need a recommendation for a low current DC clamp. Either a stand alone or one to be used with a DMM. What I use it for is to trace a short. Generally I would have a machine powered by a 24VDC power supply that powers a lot of circuits. If there is a short in one of the wire it will kill the output of the power supply. What I want to do is to remove the power supply and substitute it for one with current limiting and limit the current to a relative low current. Then with an amp clamp I can check the current flow thru the whole bunch of wires that attached to the DC bus one by one. The one that draws a lot of current would be the one. So the clamp should have relative small jaw as there wires are small, 20 or 18 AWG. Accuracy isn't important. I need resolution but not accuracy and I don't want to pay big buck.

author: nctnico
author_rank: Super Contributor
timestamp: October 28, 2024, 02:58:27 pm
content: A thermal camera is likely more suitable as this will also show the point where the short is (literally a hotspot in most cases).

author: BeBuLamar
author_rank: Super Contributor
timestamp: October 28, 2024, 03:03:40 pm
content: Not enough current to produce enough heat for that. Generally the normal power supply when it got such a short would shut it down on over current so there is no chance to detect the heat. When I power it up with a power supply with current limiting but not shutting down on dead short I have relatively low current and not much heat.

author: RAPo
author_rank: Super Contributor
timestamp: October 28, 2024, 03:11:55 pm
content: Does thefit your requirements and price bracket?

author: aluminumfoilteslacoil
author_rank: Newbie
timestamp: October 28, 2024, 03:22:45 pm
content: Wow, that Owon seems like a great value. Under $40 from what I'm seeing. A Fluke that does DC current is well over $300.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: October 29, 2024, 05:39:32 am
content: Have you used the forums search function?IMO it has been debated to the moon and back, which current clamps are suited for which use cases.Would be the best place for you to start.

author: BeBuLamar
author_rank: Super Contributor
timestamp: October 29, 2024, 11:42:04 am
content: Quote from: DaneLaw on October 29, 2024, 05:39:32 amI found nobody talking about using a current clamp to trace a short circuit.

author: tszaboo
author_rank: Super Contributor
timestamp: October 29, 2024, 11:55:46 am
content: Quote from: BeBuLamar on October 29, 2024, 11:42:04 amIf your power supply has a latch-off function, indeed it could be annoying to trace a short circuit in wires. If you cannot disconnect the wires to eliminate the issue, then a clamp might work. I have the UT-210E that I bough for about 30 USD years ago, somehow it's now cost twice as much.In my experience you get maybe 600mA residual magnetic field/earth magnetic field on the lowest range (2A DC), that you need to zero out, and then move the meter as little as possible.

author: The Soulman
author_rank: Super Contributor
timestamp: October 29, 2024, 12:05:39 pm
content: For your use case I can recommend the Peaktech 4250 (or equivalent).Smaller jaws and not having to twist your head in a awkward position to read a display is a real plus imho.You may need to do some easy mods:https://www.eevblog.com/forum/testgear/peaktech-4250-acdc-current-clamp-teardown-and-repair/msg1398936/#msg1398936

author: RAPo
author_rank: Super Contributor
timestamp: October 29, 2024, 12:51:09 pm
content: You can buy the Owon in bluetooth variant, displaying the data in an app on your phone ...Quote from: The Soulman on October 29, 2024, 12:05:39 pm

author: BeBuLamar
author_rank: Super Contributor
timestamp: October 29, 2024, 12:59:52 pm
content: Quote from: tszaboo on October 29, 2024, 11:55:46 amMost of the machines I work with has power supply that shut themselves off when overcurrent. You have to disconnect them from the AC input and reconnect them to make them work again. I can remove the wires but there can be 20, 30 or even more wires connected to the same power supply. It's a real pain. I currently use a Fluke 374 and it does work however there are 2 things I don't like about it. It only read down to .1A and the jaw is big and hard to get to a single wire in a bundle.

author: vlelectroniclab
author_rank: Contributor
timestamp: October 29, 2024, 01:04:36 pm
content: Hi,I recommend you an APP MA5, it has a good resolution for small currents.Consider that they produce for benning germany.