Mot Bank construction question

[guest]

The 15 kv solid state neon "former" was an utter dud.
I have moved on to mots as real iron neon transformers don't seem to be real availible right now.
I have successfully banked four mots together for an output of 8 kv. Doesn't run too hot surprisingly for a lashed together freebee. My next task is to is to add two mots at a time and see if I can squeeze 16 kv out of them.
My intention is to run them at 15 kv at .5 amp.
Do I really need to run this unit under oil if I use the right value of hv wire and completely cover the terminations in Rtv? I know my pulse unit will need an oil tank.
I was kinda hoping to air cool the transformer bank.
I will post pictures no matter what happens.

Larry Leins
Physics Teacher

[guest]

Larry,
On a similar project, I had no problem using solid core automotive ignition wire(Moroso Blue Max). I pushed this up to about 25kv in the open air.

On your MOT's; How much current does that draw off your mains when its under load ?

Also, you may be able spoon feed 220 into the primary with a variac. This way, 175 volts or so should be able to give you the desired output. If your worried about primary overload, then use the extra two MOT's in a parallel configuration on the front end. This should be more efficient, and safe.

Mark Rowley
Garage Scientist (Unlicensed)

[guest]

Hi Larry, I think your main limiting factor with MOT's is going to be the last couple of tranny's in the line will have a voltage almost too great for the bobbin to cope with and it may arc to ground via the laminations or the primary. I've salvaged the iron off MOT's to wind high current chokes with and the lack of insulation those things have worries me. Oil immersion may give that extra margin and at least
the laminations can safely float then. Also I found the VA ratings they give those things must be extremely optimistic and based on a short duty cycle.

regards
Mark Harriss

[Richard Hull]

It is highly unlikely that you will even warm the transofmrers or that you will need 500ma continuous draw from them. (that would be 4kva! No fusor needs that and no grid known to man could survive it.

Insulation of the high end of your xfrmr chain could be an issue. With pulsed operation insulation breaks over much easier than with static DC levels. No suggestions here.

Richard Hull