|[AMRadio] Tranny Test|
rickbras at airmail.net
Mon Feb 19 15:45:12 EST 2007
Bingo! That should tell me exactly what I need to know. Thanks, John!
John Lawson wrote:
> 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.
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