[TCML] MMC for 4 mot SRGTC

[bartb]

Hi Kris,

Something else to keep in mind regarding the primary is the coupling. 
The primary needs to start at a distance of 1.5 inches from the 
secondary in order to keep the coupling optimal at the forefront of the 
design. 1.5" will allow a flat primary to be positioned directly 
horizontal with the bottom secondary turn and you'll have very little 
need to adjust coupling later. I assume the secondary is wound with #24 
or #22. Either would do well.

When I look at what distance to start the primary at, both standoff 
voltage and coupling are the values I look at. Javatc has a recommended 
distance for this in it's output, but the distance is based on voltage 
standoff. However, if I see coupling is too high, then I increase 
distance until I near the recommended k value for the coil, and in your 
case, probably in the vicinity of 0.135 k.

I am curious what your sec dimensions are? Also, have you already built 
the primary for this MOT supply?

Take care,
Bart
> Kris Grillo wrote:
>> I am putting together a 6" coil with 4 MOT power supply and a 120 bps 
>> sync rotary gap.  I would like to run the mots wide open (no 
>> ballast). I estimated 8400 V .5A for the transformer output. For the 
>> MMC, JavaTC is saying I need .4117uf for LTR! That seems huge to me. 
>> I have 60 of the 942's for 5 strings of 12 right now, and I planned 
>> on doubling that to get to .1249uf before I get it up and running, 
>> but that is still less than resonant. I could probably swing another 
>> 84 caps to get to 12 x 12 for a just about resonant cap, but 336 more 
>> caps for the .4117uf value is a little out of my price range right 
>> now. Is it so important to run larger than resonant cap with a mot 
>> driven srg coil? The mots are under oil, if that matters. Any 
>> suggestions?