[Prev][Next][Index][Thread]
RE: Transformer Proctection Circuits?
> -----Original Message-----
> From: Tesla List [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, January 19, 2000 10:24 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Transformer Proctection Circuits?
>
>
> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>
> At 09:20 AM 01/19/2000 -0500, you wrote:
> >
> >Hello Fellow Coilers,
> >
> >I have read about a three styles of transformer proctection
> >circuits to date. Does anyone have and ideas on which is best
> >or possibly an even better method? Following are
> >the three I have heard about.
> >
> >1) A RF choke on each of the secondaries output.
> >2) A resistor on each of the secondaries output with one
> >small capacitor paralleling the secondaries.
> >3) A resistor on each of the secondaries output with
> >two small capacitors hanging off the secondaries output
> >going to ground.
> >
> >
> >
> >Many Thanks,
> >Bill Parn
> >
>
>
> Hi Bill,
>
> Option (1) is falling out of favor these days. When one
> adds a 100mH
> choke to the 500+H inductance of an NST secondary winding, the external
> choke simply does not do anything. Any transients will still
> appear across
> the secondary winding. Some suspect that very high frequency transients
> will build high voltages in the first few layers of the secondary
> since the
> inductance is so high.
>
> Option (2) gives a much more effective RC network but
> without a ground
> reference, a secondary to primary strike may send both of the secondary
> windings over voltage since there is not much holding them back.
>
> Option (3) is my favorite. It gives good high frequency
> attenuation and
> the caps referenced to ground help insure that the secondaries
> cannot float
> to a great voltage. I also use MOVs and spark gaps in the protection
> filter. I have a string of 1800V 2500A MOVs from each secondary leg to
> ground. On the spark gap side of the protection filter, I have a
> spark gap
> with each leg referenced to ground. With this filter and MMC caps,
> secondary to primary strikes should be fully protected against. I do not
> use strike rails.
>
> Cheers,
>
> Terry
>
>
>
>
Hi Terry,
Do you by any chance have a diagram on the web I can take a
look at showing your protection circuitry?
Many Thanks,
Bill