RE: Explanation of K

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

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


CJ -

In my Tesla Coil Design Manual I show a test to find the mutual inductance
and the K factor of your coil. The derivation is from the basic equation

   V = Lm di/dt  where V is the voltage in the secondary coil and di the
current in the primary coil.

For 60 Hertz the dt = 1/(6.283x60) = 1/377

The mutual inductance Lm = V/(377xIp)

The K factor = Lm/sqrt(LpxLs)

This simple well known test solves the differential equation
          L = V di/dt

John Couture

--------------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, December 14, 2001 7:57 PM
To: tesla-at-pupman-dot-com
Subject: RE: Explanation of K


Original poster: "CJ Moore by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<wizard1234-at-home-dot-com>

I understand that aspect, but I am still confused about how the test was
derived and the theory behind it.



-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, December 14, 2001 10:51 AM
To: tesla-at-pupman-dot-com
Subject: Re: Explanation of K


Original poster: "Jason Petrou by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jasonp-at-btinternet-dot-com>

CJ,

Basically the coupling (K) determines the rate of voltage rise in the
secondary coil. A low coupling will mean a relatively slow voltage rise and
poor energy transfer, because the primary rings for longer and wastes more
energy. A very high coupling will mean a fast energy transfer, but a great
potential difference in the secondary. The fast rising difference between
the top and the bottom of the coil causes the racing arcs. The trick is to
couple as tightly as possible without racing arcs.

Best Regards,
Jason

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Geek #1139 - G-2 - www.thegeekgroup-dot-org
"You can never have too many volts, amps, gigabytes, wire, money or duct
tape"
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----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, December 14, 2001 3:03 AM
Subject: Explanation of K


> Original poster: "CJ Moore by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<wizard1234-at-home-dot-com>
>
> I have found several tests to find the coupling coefficient, and think
that
> I will prob. go with the one everyone seems to agree is the best. What I
> haven't found is why the test works, or how it was derived. I am doing a
> science fair project on this and am in need of a little technical help.
Any
> information or links would be appreciated. You can email me off list at
> xowoe-at-home-dot-com if you would prefer.
>
> Thanks again,
> CJ
>
> P.S: - a pic of my partially completed coil can be seen here... it was a
> quick pic with no setup, and a bad job cleaning it up, but expect many
more
> pics (and possibly dv) of the coil when its completed
>
> http://members.home-dot-com/fredmoore/coil.gif
>
>
>