Isolation transformer source
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From: GregS on 14 Jun 2010 09:20 In article <5126528e48dave(a)davenoise.co.uk>, "Dave Plowman (News)" <dave(a)davenoise.co.uk> wrote: >In article <j7g716l13t96u9322qmqjiv8r5ppua3tdj(a)4ax.com>, > <PlainBill47(a)yahoo.com> wrote: >> That would be news to large numbers of electronics technicians who had >> to use an isolation transformer when servicing TVs and other 'live >> chassis' consumer electronics. There IS a reason the advice was 'to >> always keep one hand in your pocket'. > >If using a proper isolating transformer, there will be no reference to >ground even with a 'live' chassis. The only way to get an electrical shock >is to touch both outputs from the transformer. > Proper is the key. I would say over 98% of so called isolation transformers are for noise control, not serving chassis. Greg
From: GregS on 14 Jun 2010 09:32 In article <hv5a59$h02$2(a)usenet01.srv.cis.pitt.edu>, zekfrivo(a)zekfrivolous.com (GregS) wrote: >In article <25q616l11jlnq0o0gtut5vu5p4el4fiscl(a)4ax.com>, JW <none(a)dev.null> > wrote: >>On Fri, 11 Jun 2010 08:24:36 -0500 Chuck <ch(a)deja.net> wrote in Message >>id: <r7e416tt40mloqh91evegbjo9eb2qllqjk(a)4ax.com>: >> >>>On Thu, 10 Jun 2010 09:44:12 -0400, JW <none(a)dev.null> wrote: >>> >>>>Can anyone recommend a good isolation transformer for sale on-line? >>>>Need one that will handle 5 amps or so at 120VAC, and have a standard AC >>>>plug at the outlet. Prefer one for less than $100 or so, unless that seems >>>>unreasonable. Found one at Mouser for $114 but that's only good for 1.25A. >>>>Getting lots of irrelevant hits on google... >>>> >>>>Thanks. >>> >>> >>>MCM Electronics has one. Chuck >> >>Thanks Chuck. Looking at these for the moment: >>http://www.mcmelectronics.com/product/TRIPP-LITE--POWER-PROTECTION--IS500-/28- >1 >>0160 >>http://www.mcmelectronics.com/product/TENMA-72-1097-/72-1097 > >The Tripp-Lite device has secondary attached to GROUND. This is NOT >want you want. All Tripp-Lite supplies are attached to ground forming a new > neutral to >make a noise reduction device, period. This is the description in the specs............... Neutral to ground bonding at the secondary eliminates common mode noise and provides an isolated ground reference for sensitive equipment What they really mean is a new ground to neutral reference. They make it confusing. For testing chassis, you need a ground isolating isolation transformer. greg >I hope the second device has ground isolation. > >Greg
From: Chuck on 14 Jun 2010 10:58 On Sat, 12 Jun 2010 07:01:32 -0400, JW <none(a)dev.null> wrote: >On Fri, 11 Jun 2010 08:24:36 -0500 Chuck <ch(a)deja.net> wrote in Message >id: <r7e416tt40mloqh91evegbjo9eb2qllqjk(a)4ax.com>: > >>On Thu, 10 Jun 2010 09:44:12 -0400, JW <none(a)dev.null> wrote: >> >>>Can anyone recommend a good isolation transformer for sale on-line? >>>Need one that will handle 5 amps or so at 120VAC, and have a standard AC >>>plug at the outlet. Prefer one for less than $100 or so, unless that seems >>>unreasonable. Found one at Mouser for $114 but that's only good for 1.25A. >>>Getting lots of irrelevant hits on google... >>> >>>Thanks. >> >> >>MCM Electronics has one. Chuck > >Thanks Chuck. Looking at these for the moment: >http://www.mcmelectronics.com/product/TRIPP-LITE--POWER-PROTECTION--IS500-/28-10160 >http://www.mcmelectronics.com/product/TENMA-72-1097-/72-1097 > >A bit more than I wanted to spend and a little less current capability, >but those may be the breaks. Check out stock number 72-6670 isolation transformer $65.00. We've had one for years and it works very well. Chuck
From: Dave Plowman (News) on 14 Jun 2010 13:07 In article <bv8c16h71hdp340kc6d0scspkddjqrufdp(a)4ax.com>, PeterD <peter2(a)hipson.net> wrote: > >Yawn. You really do need to sort out how to work in a safe environment. > >All it needs is some common sense. Do you ground one side of a battery DVM > >too? > Dang, you confirm stupidity... Amazing! Any test equipment DESIGNED to > not be grounded isn't grounded. And test equipement that is designed > to be grounded damned well better be grounded. If you are isolating the equipment you're working on for safety reasons doesn't it make sense to use isolated test gear too? -- *How can I miss you if you won't go away? Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound.
From: Dave Plowman (News) on 14 Jun 2010 13:08
In article <hv5a8i$h02$3(a)usenet01.srv.cis.pitt.edu>, GregS <zekfrivo(a)zekfrivolous.com> wrote: > >If using a proper isolating transformer, there will be no reference to > >ground even with a 'live' chassis. The only way to get an electrical > >shock is to touch both outputs from the transformer. > > > Proper is the key. I would say over 98% of so called isolation > transformers are for noise control, not serving chassis. Then they should have a different name. -- *If you don't like the news, go out and make some. Dave Plowman dave(a)davenoise.co.uk London SW To e-mail, change noise into sound. |