Re: NST protection

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

Original poster: "Gregory Hunter by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ghunter31014-at-yahoo-dot-com>

Hi Justin,

Your microwave oven cap NST protection scheme is
flawed. However, you can certainly use high voltage
bypass caps in a simple lo-pass filter arrangement to
protect your NST from RF feedback. A filter & safety
gaps will protect NSTs about as well as they can be
protected from the harsh RF currents produced by the
disruptive type tesla coil. Another possibility is to
rectify and filter the output of your NST to make a DC
power supply, perhaps using a bank of MOT caps for the
output filter. This would offer a high degree of RF
isolation between the NST and the tesla tank circuit.

Terry Fritz has a diagram for the ultimate NST filter
on his site. I have a cheaper, simpler version on my
site. You can build an effective lo-pass filter for a
fraction of the cost of a used 15/60 NST. I think it's
money well spent.

Best Regards,

Greg
http://hot-streamer-dot-com/greg

--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <Cydesho-at-aol-dot-com>
> 
> Well, I burned out another one of my 15kV 60mA NST's
> today. That's the second 
> one, and I've only got one left. After the cursing
> stopped, I got to 
> thinking. After I while, I came across an idea for
> protecting NST's. I don't 
> know if it will work, but I'll ask you guys and see
> what you think. A couple 
> of days ago, I was asking about using microwave oven
> caps as a tesla tank 
> capacitor. Everyone that responded told me that they
> won't work because they 
> are lossy at RF frequencies. They are intended for
> use at about 60 Hz. So 
> here's the idea: Why not place lossy type capacitors
> between the tesla tank 
> circuit and the NST. I'm not an electronics expert,
> so someone would have to 
> come up with a proper setup. The 60Hz coming off the
> NST would pass through 
> the caps without any problem, but any RFI coming
> back through the circuit 
> would be turned into heat before it could damage the
> NST. Of course some 
> other type of capacitor could be used beside
> microwave oven caps, which would 
> be quite bulky. I have no idea if this will work,
> but I thought I might as 
> well throw it out there. I'd like to know what some
> of you guys out there 
> think.
>                                 Justin
> 
> 
> 


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