Re: Primary Scoping

To: tesla-at-grendel.objinc-dot-com
Subject: Re: Primary Scoping
From: jim.fosse-at-bdt-dot-com (jim fosse)
Date: Tue, 27 Feb 96 00:08 PST
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I wrote,
>On the subject of scoping the primary, Jim wrote....
>
>>         I was woundering if anybody had hooked a high voltage divider up to
>> the primary of a TC and observed the waveform, measured the spark gap quench
>> time or performed any other measurements? I've got an 20KV RF rated voltage
>> divider and a dozen or so Dale HV-2 100Mohm resistors. Any thoughts on
>> safety? I'm a degreed EE but haven't done any HV work and want to make sure
>> I'm safe before I'm sorry.

Malcolm wrote,
>
>I have scoped primary operation and am shortly about to do more, but
>first - I haven't scoped one using a resistive divider. I have used
>Mark Barton's technique of dangling an aerial from the scope lead
>some way off to see what was happening. Very interesting indeed. The
>scoping was only done with single-shot operation. I haven't yet
>scoped a coil under AC running conditions.

Works well for continous operation. I don't have a storage scope so I HAVE
to watch steady state signals.

> Also, I haven't run a quench gap as yet.  [snip]

I sort-of did that last night. RQ's cylindrical gap with and without 90cfm
of industrial blower running. Could not see a lot of difference in the
signal, no difference in spark length, medium difference in spark energy.


>     I am shortly going to calculate the frequency split values (ex-
>pressed as F(hi) = yF(lo) where y is a multiplier) for the sweet
>values of k. I'll post when I've done it. Knowing the correct fre-
>quency split will enable coupling to be tuned to a particular
>value BEFORE power is applied to the coil.

Yep,    you can watch the beat between the 2 on the scope. I know the theory
of mutially (bad sp, 4 tries, to late at night) coupled inductor frequency
split, but whatching it in the scope looks like a sine wave amplitude
modulated with the beat freqency.                       
                                                        

[snip]
>Please keep us posted on this. I am VERY interested.
>
will do

                        jim