Re: Filters & Chokes

["sundog" <sundog-at-xxxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Hi all,

 For my $.02, I've never run a vairac on a coil.  I just throw the
switch (okay, contactor) and let it rip.  A varaic is nice, but not
necessary, plus, once you reach the higher current levels, a variac
gets expensive, be it a single unit, or ganged units.  For pig
powered systems, I'd be more concerened controlling the current vs
controlling the voltage.  Just my humble opinion :)

Sundog

-----Original Message-----
From: Tesla list <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Monday, November 13, 2000 8:52 PM
Subject: Re: Filters & Chokes


>Original poster: "Gregory Hunter" <ghunter31014-at-yahoo-dot-com>
>
>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
>>
>>
>>
>
>
>__________________________________________________
>Do You Yahoo!?
>Yahoo! Calendar - Get organized for the holidays!
>http://calendar.yahoo-dot-com/
>
>
>
>