isolation transformer needed
in [Repair]
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From: Dave Plowman (News) on 2 Dec 2009 19:29 In article <hf6di4$97m$1(a)usenet01.srv.cis.pitt.edu>, GregS <zekfrivo(a)zekfrivolous.com> wrote: > >That's interesting. I've never seen any transformer with the secondary > >tied to ground - unless as part of an installation. The word 'isolation' > >means just that. Sure you're not thinking of an auto transformer? > I have been thinking about it. The MAIN purpose of an isolation > transformer is to make it non isolated by making a NEW neutral close to > the device being powered. The main purpose of an isolation transformer > is noise control. > Now we have us tecks who all our lives have learned isolation and that > stuff. I taliked to the people at Tripplite and verified ALL their > isolation transformers ARE grounded. Read the paragraph, and yet it says > above, "Complete line Isolation" > http://www.tripplite.com/en/products/model.cfm?txtSeriesID=325&EID=13703&txtModelID=230 > Also look through > http://www.tripplite.com/en/keyword-search.cfm?q=isolation%20transformer > The isolator you buy from MCM is very unlikely to have the secondary > grounded, but I really can't verify that. It could be down to how power is distributed in our different countries. Effectively in the UK as regards power outlets there is only one voltage (240v) and all will be on the same phase. And the neutral is at ground potential. Without any form of protection, touching the neutral is safe. Touching the live isn't. With an isolating transformer, you can touch *either* safely, as there is no potential to ground. The only power outlet allowed in a UK bathroom is a shaver socket - and that is fed via an isolating transformer. -- *Aim Low, Reach Your Goals, Avoid Disappointment * Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound.
From: whit3rd on 2 Dec 2009 20:13 On Dec 1, 7:41 pm, sbnjhfty <fgsdf...(a)asfffwer.com> wrote: > I'm looking for an isolation transformer for repairing small (less > than 1000W) power supplies. I see loads of them on ebay and some are > medical grade and inexpensive. Are these usable for what I want? Yes, they are. In terms of shock hazard, you can use a GFI to the 1000W unit, and a small isolation transformer to run your oscilloscope, and get the same kind of result. The best isolation transformers are made for RF passthrough protection, or medical equipment uses, and will work well for the less-demanding electronics workbench even when they're 40 years old... so buying a used one makes sense.
From: mm on 2 Dec 2009 23:55 On Wed, 2 Dec 2009 17:13:20 -0800 (PST), whit3rd <whit3rd(a)gmail.com> wrote: >Yes, they are. In terms of shock hazard, you can use a GFI to >the 1000W unit, and a small isolation transformer to run your >oscilloscope, Do they make plug-in GFI's? Like they make plug in surge supressors and plug-in adapaters from 3 pin plugs to 2 slot receptacles, it should be easy to make a plug-in, point of use GFI, but I havent' come across one.
From: mm on 3 Dec 2009 01:26 On Tue, 01 Dec 2009 22:41:38 -0500, in sci.electronics.repair you wrote: >I'm looking for an isolation transformer for repairing small (less >than 1000W) power supplies. I see loads of them on ebay and some are >medical grade and inexpensive. Are these usable for what I want? >Other than that, any tips on where to get a good deal on one? I >don't want to spend a load as this is hobby work only. Now you've got me going and I want one too, but the biggest I saw today was 385 va, and it's listed as new, not surplus (which is what I thought you meant. They're 23 or 30 dollars plus 12 dollars shipping) I see one for 8 dollars but it's only 100va. Maybe I misunderstand your requirements, or my own :) . I'll wait as long as you tell me to, and I'm not going to bid against you, but you say there are loads of them. Can you give me a url or item number so I can see what you're talking about. I'd appreciate it. Mike
From: Rheilly Phoull on 3 Dec 2009 05:10
"sbnjhfty" <fgsdfgrr(a)asfffwer.com> wrote in message news:%llRm.94141$gg6.27160(a)newsfe25.iad... > I'm looking for an isolation transformer for repairing small (less > than 1000W) power supplies. I see loads of them on ebay and some are > medical grade and inexpensive. Are these usable for what I want? > Other than that, any tips on where to get a good deal on one? I > don't want to spend a load as this is hobby work only. So what do you want it for, to cut down on noise when you contact the "live" when working on the PSU or to avoid shocks whilst working on the gear ?? Regards......... Rheilly P |