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Re: Beginner Measurements



Tesla List wrote:
> 
> > Subject: Beginner Measurements
> > Subject: Quick and Dirty resonance check
> 
> >From hullr-at-whitlock-dot-comThu Oct 24 22:22:23 1996
> Date: Thu, 24 Oct 1996 10:55:52 -0700
> From: Richard Hull <hullr-at-whitlock-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Beginner Measurements
> 
> Tesla List wrote:
> >
> > Quick and Dirty resonance check
> >
> > >From jparisse-at-ddlabs-dot-comWed Oct 23 21:37:51 1996
> > Date: Wed, 23 Oct 1996 10:49:27 -0700
> > From: "Jeff W. Parisse" <jparisse-at-ddlabs-dot-com>
> > To: tesla-at-pupman-dot-com
> > Subject: Beginner Measurements
> >
> > All,
> >
> > I just started using a tip from Richard Hull to measure the resonant
> > freqs of our tesla coils and I feel as if I've discovered the "next
> > level" (a self realization... I know you guys already know this stuff).
> > I'll repost the tip at the bottom of my post...
> >
> > My questions are... Now hungry for more actual readings (instead of
> > computer projections or forumlae) I want to know if there is a way to
> > measure primary resonance with a VOM, Frequency Counter and Frequency
> > Generator (old Heathkit 1Hz - 1MHz, 10V)?
> 
> Yes, Gary Petersen had a nice article in the TCBA news some ten years
> ago, can't remember the issue, on primary measurement.  But why do it?
> Who cares!  What ever you find will definitely be incorrect!
> 
> 
> I find the resonant frequency of my loaded resonator,...in place.  Next I
> use the standard frequency equation for caps and inductors solved for L=
> ( .0253/(Freq squared X tank capacitance) ) This gives me the theoretical
> tap inductance on the primary.  I now use an inductance meter to locate
> that point on the primary and then just ingore it and grab one extra full
> turn!  Fire it up....  Move tap to max spark from there.  Usually optimum
> tune is found to be from 1/2 turn to 1.5 turns more than the theoretical,
> calculated tune point.  This ultimately depends loading and geometry.
> 
> Richard Hull, TCBOR
> 


Richard -


  I have a question - the added 'extra' inductance from the theoretical
lowers the frequency. That's a given. What I am wondering is that aside
from the additional 'loading' effects on the secondary, are we dealing
with some dI/dT stuff in the primary inductor itself? Obviously, the
primary's magnetic field isn't going to appear instantaneously, so I am
wondering if there are some impulse-delay factors involved.

- Brent