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Re: DC supply

Subject: 
        Re: DC supply
  Date: 
        Sun, 30 Mar 1997 03:10:21 -0700
  From: 
        "DR.RESONANCE" <DR.RESONANCE-at-next-wave-dot-net>
    To: 
        "Tesla List" <tesla-at-pupman-dot-com>


To: Chuck Seguin

The DC laser power supply does not have sufficient current to adequately
drive even a small size Tesla oscillator.  A neon sign transformer such
as
a 12 KV 60 ma unit would do a much better job.

A synchronous rotary spark gap is essential a high speed switch that is
synchronized to the 60 HZ AC line that is charging the Tesla oscillator
capacitors.  As an example a salient pole synchronous 1800 RPM motor
used
with 4 rotatating electrodes would allow you to fire at the peak of the
AC
waveform.  Actually best point is usually 10-15 degrees beyond peak. The
rotor is loosened and rotor is manually adjusted on the motor drive
shaft
-- system is run again and an O-scope checks to see if you are firing on
the peak -- if not, again more adjustment of the rotor on the drive
shaft
until your RSG electrodes are in alignment with the poles of the drive
motor.   

While synchro types of RSG's (rotary spark gap) do produce much higher
peak
current in the secondary discharge they do not usually produce longer
sparks than a non-synchro RSG.  The non-synchro gap cap effectively
fires
more times per half cycle which in turn pumps the tremendous ionic field
above the secondary HV terminal and the sparks actually "grow" outward
to
produce longer discharges.  We must also assume your power supply is
capable of re-charging the HV capacitors quickly (faster than 30
milliseconds).  This is usually the case in all but the most strained
power
supply configurations. 

 Running a Tesla coil on DC is possible but the quenching problems
become
more serious.  DC does not quench as well as AC because the waveform is
not
reversing -- this reversing helps the quenching action somewhat.

Hopes this helps out -- have fun with your power supply.

DR.RESONANCE-at-next-wave-dot-net


----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-poodle.pupman-dot-com
> Subject: DC supply
> Date: Thursday,March 27,1997 9:49 PM
> 
> Subject: 
>         DC supply
>   Date: 
>         Thu, 27 Mar 1997 09:58:10 -0500
>   From: 
>         chuck seguin <seguinc-at-algonquinc.on.ca>
>     To: 
>         Tesla List <tesla-at-pupman-dot-com>
> 
> 
> Good morning everyone,
> 
> Here is a question that puzzles me.
> 
> I have aquired a great XFMR from friends at a local college.  It was
> used, at the time, for a TEA laser power supply.  It's a 30 kV -at- ? mA. 
> The interesting portion of this is the fact its a DC supply.  It's got a
> full wave bridge connected accross the output.  The whole thing is
> submerged in XFMR oil.  Now the question: can I use a DC supply
> appropriatly to operate a large system, or small one at that?
> 
> Please comment with a detailed explanation.
> 
> Another question.
> Why is a synchronous, rotary, gap called that way?
> My studies indicate that the best time to fire the gap is at the peak of
> the AC waveform, to transfer the max energy.  How is this accomplished
> when you have a rotating gap that is started (the motor that is) at we
> don't know when, on the AC waveform?  Or do we have something that does
> "synchronize" the firing of the gap with the peak of the AC waveform.
> 
> The two questions do relate, for me.  If I use a DC power supply (full
> wave rectification actually) how will a fire the gap appropriatly
> 
> Thanks in advance.
> 
> Chuck