On Thursday 31 December 2015 16:20:40 John Thornton wrote: > On the 120v side if I measure from the hot to the ground I get 79 > volts, if I measure from hot to neutral I get the expected 128v... > what is that telling me? > > JT
My first guess is that the Bridgeport itself, is not grounded. It really should be, just to keep it from becoming lethally hot when somethings insulation fails. Generally speaking, if I can measure more than a volt between neutral and the static ground, it concerns me UNLESS its a wild phase , which I don't believe you have since its not a 3 phase circuit. TBE if something is running that uses that neutral you might see more volts, but I'd re-measure after turning whatever it was off. As to the 79 volts, I would put a small light bulb (7.5 watt night lite) from the Bp frame to neutral to see if there is any real current, or its just capacitative coupling. If capacitative coupling, a 7.5 watt night light bulb will remain dark, and that voltage should drop to less than 1 or 2 volts. If it lights up at all, and the voltage doesn't drop drastically, there really is a fault someplace. I'd start disconnecting motors for starters. Happy New Year John. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
