Re: Transformer Q's

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Charles Hobson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <charles.a.hobson-at-btinternet-dot-com>

Original poster: "Jonathan Peakall by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <jpeakall-at-mcn-dot-org>

Howdy All,

I have a used oil burner ignition transformer, given to me because it is
weak.

Transformer: Francefromer 120vac primary, 10,000 secondary at 28 ma.,
secondary mid point grounded.

My questions:

One side of the transformer reads 11.6k ohms, the other 108.7 k ohms. I
assume the side with the higher resistance is the "weak" side. Anyway to
figure out what voltage I am likely to get out of this puppy? And here
is a real duh question: I assume to connect to the mid point ground I
attach a wire to the case of the transformer? Just wanna make sure. Just
how serious a shock can it produce? And if I use 7.5 kv caps with it,
are they likely to blow on short runs? I don't have quite enough to make
a series parallel setup.

Thanks again all.

Jonathan Peakall

Hi Jonathan,

I am responding to the part about the transformer resistances only. I went
through two Boiler ignition transformers and in both cases the secondary
resistance measurements were lower after failure. Internally I found carbon
tracks. Cleaning them up corrected the problem and the resistance went back
to the higher value. One possible test, if you are VERY careful, is to
connect a make shift spark gap across each side of the transformer, apply
power and see which side arcs. The good side should give a better arc than
the bad side of the secondary. Make shift spark gap: two pieces of wire with
the gap between them set to about a 1/4" or so. If you feel uneasy about
doing this, don't bother. Such transformers are relatively inexpensive
anyway.

Cheers

Chuck