Re: NST Filter

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Jason,

At 06:22 PM 6/7/2001 +0100, you wrote:
>Hi Terry,
>I am usng an NST for the first time (kind like and upgrade from MOTs) and
>have got a couple of questions about your filter which i will use (of
>course). Firstly is it suitible for a 10/100? 

Sure.  You may want to use less MOVs.  They are 1800V clamps much like
zenor diodes.  They appear as an open curcuit until the voltage gets to
1800 when they act like a hard short.  Thier tolerance is 10% so well
assume they are on the low side at 1620.  A 10kV transformer has a peak
voltage of 10k x 1.414 = 14140 volts.  So 14140 / 1620 = 8.7 so ten (next
even number) is a good number of MOVs to have with a 10kV transformer.
That would be 5 per side.

>secondly any idea whaere I
>could get the components in the UK? 

I get them from DigiKey.  I have no idea about UK sources.

>thirdly, what are MOVs and what do they
>do, and how do they do it?

I guess they are some bulk semiconductor material that needs to have a
certain amount of voltage across them before they start to conduct.  Since
they dissipate power in a relatively large volume, they can take quite a
power hit.  Basically, they act like a switch that turns on at a given
voltage.  Perfect for shorting out high voltage spikes.

Cheers,

	Terry


>
>Thanks,
>Jason
>