Just ran the deadly mot bank.
4 mots is the limit in air.
6 mots will work in oil.
8 mots is a fantasy.
It will work for about an hour before smoke starts....
followed by bright nasty arcs.
I dont even think oil would do it.... dielectric failure near the core.
Burns like sparkler.. I did my tests at a distance with a reactive load.
It is not practical for long term work.
But a 4-6 mot supply with a tripler would work well I think.
The pulse destruction test is next... 2000 cycles at pulse duty loads.
Larry Leins
Fusion Tech
Mot bank limit
Re: Mot bank limit
Please forgive my newbie ignorance, but when you say that you're suffering dielectric failure near the core, do you mean that the secondary winding is shorting to the primary winding, via the core, on the transformers at the end of the stack? If so, this would suggest to me that you've got the secondary windings in series, but the primary windings in parallel.
It occurs to me that if you were to run a series of isolation transformers end to end, and supply each of the step up transformers off of one of the isolation transformers, that this would no longer be a problem. Granted, it would be less than ultimately efficient...
Wait, searching for surplus isolation transformers, I came across this quite interesting page:
http://home.earthlink.net/~jimlux/hv/xfrmr1.htm
It's quite clear that his transformer connecting scheme could be extended another stage, by utilizing those unused 110 windings on the outer two transformers. This would get us up into a decent range.
It occurs to me that if you were to run a series of isolation transformers end to end, and supply each of the step up transformers off of one of the isolation transformers, that this would no longer be a problem. Granted, it would be less than ultimately efficient...
Wait, searching for surplus isolation transformers, I came across this quite interesting page:
http://home.earthlink.net/~jimlux/hv/xfrmr1.htm
It's quite clear that his transformer connecting scheme could be extended another stage, by utilizing those unused 110 windings on the outer two transformers. This would get us up into a decent range.
Re: Mot bank limit
Larry -
If I understand what you are trying, the problem is the MOTs dont have enough secondary insulation to GND. Normally when transformers are "Cascaded" as you are doing, the primary of each transformer is driven by a tap at the upper end of the HV winding of the preceding transformer. If this is done, other than for the inefficiency and safety issues, you have no limit as to how many can be cascaded.... BUT.... each transformer after the first one, has to be floated above ground by the progressively higher voltage of the transformer(s) below.
Practically speaking rarely does one see more than about three in cascade.
I don't think it is anywhere near as tidy as the diode/capacitor voltage multiplier for really high voltages.
Dave Cooper
If I understand what you are trying, the problem is the MOTs dont have enough secondary insulation to GND. Normally when transformers are "Cascaded" as you are doing, the primary of each transformer is driven by a tap at the upper end of the HV winding of the preceding transformer. If this is done, other than for the inefficiency and safety issues, you have no limit as to how many can be cascaded.... BUT.... each transformer after the first one, has to be floated above ground by the progressively higher voltage of the transformer(s) below.
Practically speaking rarely does one see more than about three in cascade.
I don't think it is anywhere near as tidy as the diode/capacitor voltage multiplier for really high voltages.
Dave Cooper
Re: Mot bank limit
Hi Dave:
I did the test way back in august of last year.
It was just a sideshow.
I have progressed to the cascade voltage multiplier as my primary research power supply.
Currently I, building several (4) units that have different tasks in the lab depending on the task aim. I could not do that with separate approaches without cheap power supplies. I only have one xray tranni but many ideas. So multiplier tech fill many gaps
for cheap experimentation.
Fusion is fun!
Larry Leins
Fusion Tech
I did the test way back in august of last year.
It was just a sideshow.
I have progressed to the cascade voltage multiplier as my primary research power supply.
Currently I, building several (4) units that have different tasks in the lab depending on the task aim. I could not do that with separate approaches without cheap power supplies. I only have one xray tranni but many ideas. So multiplier tech fill many gaps
for cheap experimentation.
Fusion is fun!
Larry Leins
Fusion Tech