In article <3qdj33$
...@ixnews3.ix.netcom.com> winsk
...@ix.netcom.com (Paul Herrmann ) writes:
> In <3po9mb$
...@ixnews4.ix.netcom.com> winsk
...@ix.netcom.com (Paul
> Herrmann ) writes:
> >I am trying to replace a power transformer in a medical analyzer
> >(EG&G). This xformer requires 115\220 volt primary with three
> >secondaries. The secondaries will feed a bridge rectifier\filter. The
> >d.c. supplies are rated @: +/- 10 v.; +/- 32 v. and +/- 130 volts. All
> >secondaries must be center-tapped. Any suggestions are welcome.
> >After further testing, I have found the +/- 10 volt secondary to be
> shorted. I have also found a company in New York that will construct
> this xformer for a mere $450. Can the existing transformer be repaired?
> Any help is appreciated. Thanks, Paul.
First, you need to get the bad winding out of there - otherwise the
transformer will overheat due to the short. On a typical transformer,
this is not an easy undertaking as it is most likely buried somewhere
in one of the inner layers of windings. If it is actually open instead
of shorted, just leave it in place.
Assuming a miracle happens (or pigs start flying, take your pick),
you need to add a winding. Your best bet would still be an
external additional transformer. What is the current rating? If it
is small, you may be able to add a winding on top of the existing
transformer coils. I have no idea how many turns you will need. Wire
size will depend on your current requirements. This winding will
probably not be as well located magnetic circuit wise as the original so
its voltage vs. current regulation will not be as good as the original.
Of course, any kind of regulatory approvals go right out the window.
--- sam
