Isolation transformer source
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From: GregS on 14 Jun 2010 14:39 In article <512757b7c9dave(a)davenoise.co.uk>, "Dave Plowman (News)" <dave(a)davenoise.co.uk> wrote: >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. > Thats what I said before !!!! greg
From: Michael A. Terrell on 14 Jun 2010 15:18 "Dave Plowman (News)" wrote: > > 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? No. -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
From: PlainBill47 on 14 Jun 2010 16:41 On Sun, 13 Jun 2010 23:16:44 +0100, "Dave Plowman (News)" <dave(a)davenoise.co.uk> wrote: >In article <as-dnYa6P-Qth4nRnZ2dnUVZ_tSdnZ2d(a)earthlink.com>, > Michael A. Terrell <mike.terrell(a)earthlink.net> 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. > > >> Not true. You connect the chassis of the UUT to the test equipment, >> so ANY voltage you contact inside the UUT is referenced to ground. > >Why is the test equipment grounded? Perhaps you are a little inexperienced. There was a time when virtually ALL test equipment came with a two wire (ungrounded) cord. Then it was decided that having technicians electrocute themselves was undesirable from both efficiency and moral viewpoints. As a result, signal generators, oscilloscopes, frequency counters, alignment generators, etc all were supplied with a 3-wire cord. Thus, when an oscilloscope was hooked to a live chassis TV the probe ground burst into flames rather than the technician falling to the floor in cardiac arrest. Of course, there were those brave (or foolish) souls who cut off the ground pin on the power cord to save a few dollars. While others might disagree, I feel that using an isolation transformer is preferable to losing my life. PlainBill
From: JW on 16 Jun 2010 09:07
On Mon, 14 Jun 2010 09:58:33 -0500 Chuck <ch(a)deja.net> wrote in Message id: <ajgc16p7cqki5n2m5hntcdg2gd2okvgn44(a)4ax.com>: >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 Looks like we have a winner. Thanks again, Chuck. And thanks to all who contributed to the thread. |