You had best have something to protect that microameter when you turn on the supply as the capacitance of the transformer windings will look like a short to the meter until the charge equalizes. Running it up with a variac would be ok.
73 Gary K4FMX > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:amradio- > [EMAIL PROTECTED] On Behalf Of John Lawson > Sent: Monday, February 19, 2007 3:38 PM > To: Discussion of AM Radio in the Amateur Service > Subject: Re: [AMRadio] Tranny Test > > > > > Re: quasi-pseudo hi-pot testing of your transformer - if you have a > device that produces the required 800-1000 VDC - and can access that > voltage (such as a bench supply, one of the other power supplies in the > transmitter - or even a Ranger maybe) then [carefully!] attach the > positive lead of that source to the windings (tie the leads toggether) > thru a suitable microammeter and ground the tranny frame... any leakage > will show up on the microammeter. A panel-mount 0-20 uA DC meter, mounted > on a piece of plastic, will do. > > If you use a DVM - just insulate it well - put it in series - don't let > any part of it get near ground or you - set the meter, step back - turn on > the HV - check the reading. Shouldn't be very many microamps to ground. > Note that any significant ripple, or other AC disturbances, in the HV > source, will confuse the reading, due to capacitive and inductive coupling > of those components. Use 'pure' DC. > > Remember to tie the transformer HV leads together - the object is to > measure any current flow from the body of the windings, thru the > insulation, to the frame - NOT from one side of the winding to the other - > which would only be a few ohms DC resistance. > > > Cheers > > John > KB6SCO > DM09fg > > ______________________________________________________________ > AMRadio mailing list > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Partner Website: http://www.amfone.net > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > To unsubscribe, send an email to [EMAIL PROTECTED] with > the word unsubscribe in the message body. ______________________________________________________________ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
