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Transformer Failure
From: Kevin Radtke[SMTP:umradtke-at-cc.UManitoba.CA]
Sent: Thursday, October 30, 1997 5:34 AM
To: Tesla List
Subject: Transformer Failure
Hi All,
OK I've got a question for you guys and I hope you can help as I
am stumped. I recently (successfully) modified a 1725 rpm motor to run
sync (with the help of this list, thank you!)and I set it up so I would be
running my rotary gap at 120 pps. I observed that by rotating the opposing
points over 90' I would go from getting no sparks to a maximum and back to
none. Fine. The problem is when I had it adjusted for the maximum I would
get some serious arcing across the terminals of my Transformer (it is a 10kV
20mA oil furnace ignition transformer with two HV terminals on top 1" apart)
Anyways the entire performance of the coil was drastically reduced and
the new rotary gap smoked my trannie. Ouch. I do have a safety gap in
parallel with some chokes as protection, but I will admit that I kept
adjusting the gap (making it bigger) in hopes of improving the coils
output. There were basically three scenerios that I observed.
For all rotary gap adjustments the gap spacing was approx 1/8"
1/16" x 2
1) Rotary gap adjusted so that the cap was humming but otherwise nothing
else going on.
2) Rotary gap adjusted so that all the arcing was taking place at the
rotary gap. Safety gap not firing. The coils output at this point was
about 6" off a point (I still don't have a torroid) where previoulsy with
a rotary gap running off a small DC motor with 12 points (I have no idea
what kind of pps) it was around 16" With a single static gap output was
around 12".
3) Rotary gap adjusted so that there was "small" but steady arcing going
on at the rotary gap but very loudd heavy arcing across the safety gap.
Spacing about 3/4" to 1" This was made bigger until I eventually blew my
transformer.
Any suggestions? I know that its my own damn fault I blew the trannie,
but I was impatient to try the new sync gap and I was dissapointed by the
results. (Happens occaisionally). Thankfully the trannie only cost me
$25. But I don't want to blow anymore of them. Thanks in advance.
Kevin