Re: MOTs/MMC

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

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Esondrmn-at-aol-dot-com>

In a message dated 4/22/03 3:19:52 PM Pacific Daylight Time, 
tesla-at-pupman-dot-com writes:


>Hi Jerry
>Yes there is a way (probably several in fact)
>
>A stack with centre gnd and 3 per side phased 180deg apart will do it.
>Oil for at least the outer 4 MOT's.
>
>I'd recommend setting up phasing with a low voltage AC source.
>
>I remove the heater windings to reduce clutter.
>
>Lift the secondary winding where it is earthed to the core and feed the
>previous MOT secondary outer into this point. Care to stabalise this spot
>with hot glue or the like.
>
>I always earth the core but some have suggested leaving it floating to
>spread the voltage stress out between the core to primary and corre to
>secondary gap. My reason is to place an earth barrier between the mains and
>HT side for safety. I do not want a stray streamer to secondary strike to be
>able to get back into the mains.
>
>I've not had any problems with 6MOT's breaking down to core in this config.
>In some operational mode I believe Iv'e pushed the potential up to at least
>25kV without breaking down the MOT (caps banged however) Did this with poor
>choice of SRSG firing times with 300bps operation
>
>Interested in your secondary Capacitive ballast. Would appreciate a post on
>the value of C you will use. I have this thing about the possibility of 60Hz
>resonance with the output inductance of the MOT stack and would like to see
>what people are doing and do a few sums on things
>Tnx
>
>
>Good luck and BTW MOT's are leathal great care
>Best
>Ted L in NZ


I have seen a few discussions lately about using capacitors in series with 
the secondary of microwave oven transformers as ballast to limit the 
current.  What is the advantage of this method over using primary inductive 
or capacitive ballast?  I realize that winding a primary ballast can be a 
pain but doesn't two or three MOTs (with shorted secondaries) in parallel 
work ok?  How about using motor run caps in series with the primary?  It 
just seems that ballasting would be easier done on the low voltage 
side.  Just curious.

Ed Sonderman