Re: MOVs for transient suppression

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

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

Hi Steve,

The MOVs are +-10% so minimum turn on is 1.1 x 240 = 264 VAC.  But, I would go
to 300 at least.  A little over voltage will do no harm but if the MOV value is
too low they will blowup.  I think one 6500 amp MOV will do just about all a
MOV can do.  I think they have like 25,000 amp MOVs for a big price but they
are not that much more effective since if you blow a 65000 amp version
something is wrong enough to get the 25,000 amp version too.  You can always
parallel them up too.

Cheers,

        Terry

At 10:07 PM 4/1/2002 -0800, you wrote: 
>
> For additional protection, I am considering adding some MOVs to the 240 AC
> input power to my power control cabinet. This is in addition to EMI filters
> which will already be in place. The idea is to provide a hard limit to any
> large voltage spikes generated by the TC. This is to protect devices
> connected the power line in my house, not the TC. Does any one have any ideas
> as what type of MOV spec I should be looking for? My initial idea is about
> 275 volts RMS with the largest current capacity that is reasonable. Digikey
> has some MOVs that handle about 6500 amps peak for reasonable prices. By the
> way, my coil is pig-powered. Opinions?
>  
> Steve: Coiling in Iowa