Re: Filters & Chokes

["Gregory Hunter" <ghunter31014-at-xxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Hi Neil,

For a protection network, skip the chokes and go with
an RC filter.  A good generic filter design is a
1k/100W wire-wound ceramic power resistor on each HV
leg, and a 500-1000pF bypass cap from each HV terminal
to ground.  Ceramic disk or "doorknob" caps are more
than adequate for this duty.

The dimmer is pretty useless for controling an NST. 
Dimmers don't really control voltage at all, but only
the duty cycle of the AC, and they butcher the AC
waveform in the process.  Also, dimmers don't work
well on complex reactive loads (such as an NST feeding
a spark gap oscillator).  Just run your NST wide open
to start with.  Later, if you feel you must have a
range of power control, you can spring for the price
of a variac.

My $0.02 worth.

Greg
www.angelfire-dot-com/ga3/tesla

--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Neil Chambers"
> <Neil_Chambers-at-paragon-it-dot-com> 
> 
> Hi
> 
> I am in the designing stages of my Tesla coil.
> 
> I am having difficulty in finding comprehensive and
> consistent information
> in the design of a filter or choke system to protect
> my NST (10kV 50mA 240V
> 50Hz)
> 
> Some pages say to avoid chokes due to inductive
> spikes, others outline RC
> filters but with no explaination of the LCR values.
> 
> Any help or pointers much appreciated!
> 
> ...Also, is it OK to use a cheapo 400W light-switch
> dimmer to control the
> input voltage to the NST?
> 
> Thanks
> 
> 
> Neil
> 
> 
> 


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