Re: new MOT stack completed!

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

Original poster: "tesla by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla-at-paradise-dot-net.nz>

Greetings.
No problems with more data and opinions

I'm a MOT fan cos they work a treat for nearly nothing.
1) None of my MOTs are the same. (but they are similar) and I doubt it
matter too much.
2) I selected them for big core size and high O/P volts.
3) The outer MOT's are selected for core to secondary insulation spacing
4) I mains ballast with big inductors from 50v rectifier sets as used by
telcos. It's not critical but saturation needs to be watched.
5) PFC needed to keep the mains I/P current down. Standard Motor run caps
are good. Not actually calculated reqd Cpfc but 100uF helps a lot
6) Coils is very standard 15deg pancake about 8T to tune. Sec is 12" dia 54"
of double spaced 22g. Resonates with toroids at 90kHz
7) Toroids are big 12" by 48" and 6" by 30" (biggest O/P is actually with
only the small toroid, time to check and tune may change this)
8) 300bps SRSG goes OK (90deg and 90+/-25deg firing) but runs more power and
bigger sparks with a multi pipe gap. Cp is 90nF MMC CD942C 1600v/0.33uF as
per Robin Copini
9) I take the MOT HT lead off its eth connection and terminate on a tagstrip
then plug that area with hot glue for stability and insulation.
10) A big variac is a good idea
11) I'm currently looking at running each half of the MOT stack (two groups
3 phased around eth) from separate mains feeds and variacs so I can more
easily achieve the required I/P current from the mains supply) Need to
ensure each is off separate feed from the switch board

It's all simplicity and common sense, any questions feel free to ask

Best
Ted L in NZ
> >Hi Ted and Tim
> >
> >I think you both should provide complete details about the tesla coils
and
> >power supplies. The expense of 5 or 10 kVA pole pigs has prevented many
> >coilers from ascending to pole pig heaven. The six pack MOT power supply
> >would allow more coilers to enter the power club. If full details of your
> >systems were made available, this could set the precedent for some
reliable
> >standards. One problem is the infinite variety of MOTs. I have about 50
> >MOTs and no two are identical in appearance. I think I remember Gregory
> >Hunter writing that he had two MOTs which were identical in appearance,
but
> >had different output characteristics. This variety alone might stand in
the
> >way of reliable standards.
> >
> >Godfrey Loudner
> -----------------------------------------------------------------------
>
> In my experience, no one MOT has exactly the same output characteristics
as
> the other! I had a 2337 VAC MOT, and a 2400 VAC MOT working together just
> fine on the same curcuit in series for my older Tesla Coil. I never had
any
> problems. But they drew around the same amount of current (9 to 10 A max).
I
> THINK CURRENT INPUT/OUTPUT/ and CORE SIZE IS THE ISSUE HERE...NOT VOLTAGE.
> So...look for Microwave with similar brand name or current draw. (the
bigger
> the current draw...the bigger the the core size--usually)
>
>
>
>