On Friday, May 25, 2012 10:58:04 AM andy pugh did opine: > On 25 May 2012 15:13, gene heskett <ghesk...@wdtv.com> wrote: > = > > > For this it gets sticky, because you have 2 choices of how to attach > > the scope probes, BOTH of which leave the case of the scope lethally > > hot, > > We had the right tool for the job on a piece of equipment I designed > once (an electric pump dynamometer). > There is something similar on eBay, but it's a bit expensive. > http://www.ebay.com/itm/310324754278
And I have doubts even Mon power has such an instrument. > There are similar things for a few $k, but that's quite a gamble on > managing to re-sell it. > > Can anything be rigged up using 3 hall-effect current sensors? Other than the fact we'd be measuring current, where we're more interested in the actual voltages in this case, which the hall effect doesn't respond to. Besides, if I wanted to measure current, I think I'd druther use current transformers. Many times the accuracy of the hall effect, 1% readily do-able in everyday use. However, that might well be a valid way to look at the load current, and what its doing to the power src, AND its a totally isolated method so the scope can remain grounded. Some scope pix there could supply some useful info, confirming where the problem lies. Needless to say, an open circuit loaded current transformer of the typical 1/100 turns ratio can be quite a waker-upper. They should be effectively shorted with a resistor only large enough in ohms to develop a usable signal. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Allen's Axiom: When all else fails, read the instructions. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
