I have in 50 ac tranny@ 40 amps , it's unmarked but is 240 primary however how to id windings , any suggestions as of course I wont be just plugging stuff in , ex telecomms
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Transformer testing
May 18, 2011
5 Replies
Well the dc resistance of the primary would be much higher than the secondary for starters. If there are taps on the primary it should be easy to identify the highest resistance pair to start off with and experiment with since if it's 415v you wont be doing any harm by hooking that up to 230v.
"Rheilly Phoull"
** For a 230 VAC primary - expect 0.5 ohmsFor the 50VAC secondary - expect 22 milliohms
A "soft start" circuit will be needed for sure - or it will trip the breaker as soon as you switch it on.
..... Phil
Like you say :-) What do you reckon to a 30R 100W with a switch across it ??
** Depends if the PSU has to come up while under load or not.
If it does, then a couple of chunky 15 amp rated, 2 ohm NTC thermistors are the go.
.... Phil
I took a quick measurement and then excited the secondary with 10 v ac , soon worked out the correct primary taps to arrive at the desired 24vac out
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