Uni-T insulation resistance meters with design problems? - Page 1
Forum section: electronics / testgear

author: belasajgo
author_rank: Contributor
timestamp: November 02, 2013, 10:32:45 pm
content: I am planning to buy an insulation resistance meter, after searching on the internet for manufacturers / models, I think I like the Uni-T UT 51x meters most. I think the UT 511 would suit my needs. After choosing the manufactuter / model, I was looking on the internet for reviews and teardowns (Dave made a teardown video with the UT 513), and I found some reviews and also videos with the UT 51x meters, where people complained about a problem with those meters turning off while testing, and / or malfunctioning. Dave also had a similar problem at the beginning of the teardown video of the UT 513. Is this a design problem of the meter?From what I saw on the internet, I think that owners of the UT 511 have more often this problem than owners of the UT 513!? Do you own such a meter (UT 51x series, especially UT 511) and have similar problems? Or is everything working ok? Is this problem only when using batteries, or also with a power adapter? (The UT 511 is normally delivered without a power adapter.)Is this a good product to buy, or should I look for another manufacturer? Thank you for the answers!

author: Lightages
author_rank: Unknown
timestamp: November 02, 2013, 11:13:36 pm
content: I have used my UT513 quite a bit and it has not failed to operate properly at any time. Mine is a sample of one so it doesn't mean much without more reports.

author: Rufus
author_rank: Super Contributor
timestamp: November 03, 2013, 01:12:36 am
content: Quote from: Lightages on November 02, 2013, 11:13:36 pmI have a UT513 and if what you are measuring arcs the processor is very likely to crash hanging the meter and often giving a garbled display. The E-STOP button is required to recover. From memory that is pretty much what Dave observed in his tear-down. Pretty shit design really, seems not to have a watchdog to at least crash gracefully. Bit dangerous also because you don't know if it is still generating the test voltage and the relay used to discharge the test voltage has normally open contacts so it doesn't even fail safe if you remove power. You would hope the E-STOP button is somehow tied in with the discharge relay (and that you have enough power to energise it).That said it seems to work OK otherwise, build quality is OK and it is very inexpensive for a 5kV meter.If you only need 1kV I think there is a lot more choice. I would prefer something physically smaller and you don't need fancy and dedicated test leads.

author: belasajgo
author_rank: Contributor
timestamp: November 03, 2013, 09:08:24 am
content: For me a 1 kV meter would suit my needs, I don't need higher test voltages, so there are more meters from other manufacturers what I can choose. But from the perspective of product robustness, build quality and accessories, I like the UT 51x meters most. I also like the big LCD screen.I will look for another meter in the same price range...

author: Wytnucls
author_rank: Super Contributor
timestamp: November 03, 2013, 09:51:03 am
content: If 1KV max is suitable, have a look at the UT530 range of DMMs. The 531 may have enough features for you, with a high range of 600MOhms, instead of 2 GOhms on the other two meters (UT532/533). All are TRMS with internal data logging (99 points). Saves you carrying 2 meters for field work.http://www.ebay.com/itm/UT531-Insulation-Tester-Megohmmeter-1000V-True-RMS-Auto-Range-DMM-2-in-1-/251120850792?pt=LH_DefaultDomain_0&hash=item3a77f81768

author: Lightages
author_rank: Unknown
timestamp: November 03, 2013, 04:26:45 pm
content: Actually I would have to go along with Rufus' assessment. When I say that mine has worked without trouble it could be construed that it works without the need to reset if you get too much arcing. Mine wil also lock up if there is too much but I don't see this as a big flaw.

author: Wytnucls
author_rank: Super Contributor
timestamp: November 03, 2013, 04:32:52 pm
content: The UT513 is discontinued, replaced by the upgraded UT513A, which doesn't have an E-Stop button anymore. So, maybe the flaw has been taken care of.It looks like the short circuit current limit has increased to 3.5mA, instead of 1.3mA on the previous model.

author: Rufus
author_rank: Super Contributor
timestamp: November 03, 2013, 04:51:14 pm
content: Quote from: belasajgo on November 03, 2013, 09:08:24 amI also have ahttp://martindale-electric.co.uk/martindale-in2102-multi-voltage-insulation-continuity-tester-p-296.htmlwhich I generally use in preference to the UT513 because it is smaller, has standard 4mm safety sockets, and runs on 6 AA batteries which using eneloops I leave in the meter all the time.It depends on how you are going to use it, for me 2.5 and 5kV was the only reason for buying a UT513.