RE: Idea ???

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

Original poster: "Steve Mach by way of Terry Fritz <twftesla-at-qwest-dot-net>" <gossamer-at-cox-dot-net>

Ok guys, here it is, the answer to our prayers.
On pg. 131 September 2002 issue of Electronics Products Mag.
Wayne Kerr Electronics
Model 6815
Impulse Winding Tester

"By applying up to 5 KV pulse and analyzing the decaying waveform detects :
Changes in material
Damaged windings
Electrical shorts
In stock
ONLY $6000.00

http://www.waynekerr-dot-com

I know I won't be going out to pick one up, but could this be simulated on a
spice program to get an idea of what parameters need to be measured ?

I haven't checked the link or started to research the theory on how this
thing does what it does.
(always been a cw and analog kind of person, pulse deficient so to speak)

And there's always Bert if I hit a dead end !

SM

-----Original Message-----
From: Dave Hartwick [mailto:ddhartwick-at-earthlink-dot-net]
Sent: Friday, September 20, 2002 1:23 PM
To: Steve Mach
Subject: RE: Idea ???


Steve,
There are actually 2 LV windings on this piglet, which I'm sure is typical.
For 240 vac operation, they are connected in series. I separated them and
measured the inductance of each. During periods when it was functioning
properly, they both measured about 10 uH. In failure mode, one measured
about 2.5 and the other about 16.5 uH. That is how it measures now in what
seems to be its finally dead state. I don't know why it's showing uH and not
mH, but the relative difference is still there. It's a Tenma LCR meter with
120 and 1000 hz modes. 120 hz mode seemed to yield the most comprehendible
data.

I guess I could use a scope and sig gen to perform the test you propose, but
we would need data points from similar known working  units for it to be
meaningful, I would think. I would not want to assume generally linear
behavior of a working unit. But...you guys know more about this stuff than I
do.
Dave



Hi Again, Here's the  Idea I wrote Terry about.
SM

Hi Terry, Sorry it's taken so long to get back to you, customer emergency at
work.
The basic idea goes as follows,
Measure and record Xl at several frequencies, say 60 to 2000 Hz.
It should remain linear with freq. (Xl=2piFL)
Would a shorted turn or turns introduce a non-linearity to Xl with
increasing freq.
Thanks,
SM
And his response.
Hi Steve,
A shorted turn should be pretty dramatic in any test. There may be a
problem that oil gets in there on opens the short until some serious
voltage gets across it. Impulse testing is usually used on these things to
find that but not easy to make one in the basement. Not sure what a good
test would be.
A low power signal generator does have an advantage of having a low
voltage that would not couple well to the other windings. So it does
isolate the winding you are looking at without the others affecting things
much.
Cheers,
Terry