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Re: Evaluation needed (fwd)
---------- Forwarded message ----------
Date: Thu, 12 Feb 1998 21:20:24 -0500
From: bmack <bmack-at-frontiernet-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Evaluation needed
Dan
Sounds like your teacher is a gutless bureaucrat! How unfortunate
that your effort and creativity was rewarded by debarment!
As long as the 60hz stuff is well protected from the curious and proper
safguards are taken, there's no problem. Did you tell him about the
RF skin effect where this RF at HV potential can only burn, not
electrocute!
I would appeal this decision to the Principal....or higher!
As for the technical explanation, it's a little rough, but the basic idea
is there.
For instance, during the RF resonance, the coil does not "break down" ( or
at
least you hope it won't). The reverse current flow is due to the collapse
of the
magnetic field when the energy from the capacitor can no longer support it.
This reverse current then recharges the capacitor (less circuit losses)
until
all the energy has been depleted from the coil,and the process repeats.
Each peak is less than it's predecessor, which results in a log decriment
"ring down" to zero. In TC's the primary ring is very short since the
object is to
transfer the energy to the secondary, where the longer ring times are
desired.
As far as the 60HZ supply is concerned, it is not part of the cicuit while
the
gap is firing since the primary is a much much lower impedance than the
NST. Think of it as charge to gap potential (optimum 1/120 second) then
fire gap, primary ring , then the process repeats.
Look up capacitors too.
Hope this helps...and don't let 'em get you down. Win it and go to the
State
fair!
Jim McVey
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-pupman-dot-com>
> Subject: Evaluation needed
> Date: Thursday, February 12, 1998 12:56 AM
>
>
> ----------
> From: Dan Ressler [SMTP:danz_da_man-at-hotmail-dot-com]
> Sent: Wednesday, February 11, 1998 5:14 PM
> To: tesla-at-pupman-dot-com
> Subject: Evaluation needed
>
> Hey all,
> Im having trouble understanding the theory of the tesla coil and the
> tank circuit. But after much pondering I have come up with an
> explination that I think makes sense......so give me your input.
>
> A tesla coil is simply a special transformer that uses the series
> resonant circuit to step up the voltage of the input power.
> A series resonant circuit consists of a coil, a capacitor, and the
> resistance of the wire. Energy is stored on one terminal of the
> capacitor and in the coil (the coil stores energy in a magnetic field,
> this is called inductance), but as the capacitor fills up the magnetic
> field of the coil breaks down causing an inductive kick (theoretically
> this would result in a voltage in the coil infinitely high and
> infinitely short, but since the capacitor fills gradually the magnetic
> field is converted into electricity gradually). This energy then
> travels back through the circuit and builds up on the other terminal of
> the capacitor, and the process repeats its self until the energy is
> damped out by the resistance of the wire. This process is synonymous to
> a pendulum swinging back and forth.
> If energy is applied to the circuit at the right frequency (the
> circuit's resonant frequency) the voltage in the system will build up to
> huge voltages (in a perfect world the voltage would reach infinity).
> This is synonymous to pushing the pendulum at the right times so that
> its amplitude increases.
> In the case of the tesla coil the transformer adds energy into the
> tank circuit, not at the resonant frequency, but the voltage still
> escalates. When the voltage is high enough it jumps the spark gap. The
> gap produces "white noise", or all possible radio frequencies, one of
> these frequencies is the resonant frequency of the tank circuit. The
> energy see-saws back and forth at the resonant frequency and the voltage
> jumps to extreme voltages.
> Next, the secondary coil absorbs the energy in the tank circuit
> through coupling. When the energy in the primary circuit reaches zero
> the spark gap extinguishes, and the above process begins again.
> Meanwhile, the secondary coil is acting as a tank circuit by its self.
> The winding of the coil have a small capacitance. The coil also has
> inductance, energy is stored in a magnetic field, and there is
> resistance. These are all the components of a tank circuit. The tesla
> coil is designed so that the resonant frequencies of the primary coil
> and the secondary coil are the same; and the secondary absorbs the
> energy of the primary coil at this frequency. The result is the voltage
> climbs and climbs as it gets higher in the secondary coil. The voltage
> gets so high the electricity can flow through even air.
>
> Tell me if this is a good explination........
> Just as a final thought, I turned in my tesla coil for my high school
> science fair project, and the teacher was scared out of his wits that I
> made this ting with his signature on the forms, he is barring me from
> entering the real science fair because he thinks it is too
> dangerous.......still I think he was very impressed
> Dan
> Danz_da_man-at-hotmail-dot-com
>
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