Re: MOT supply

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Gregory Hunter <tesla_39560@xxxxxxxxx>

I agree. The twin MOT supply with voltage doublers is
a rig job. A 4 pack of MOTs in series will yield a
simpler, more powerful, and more reliable power
supply. If you can scrounge 3 more MOTs, that's the
way to go.

Sure, the twin MOT thing works for me. By trial and
error I managed to find a Tesla coil, tank cap, spark
gap, and twin MOT supply that play well together.
Unfortunately, many coilers have trouble getting their
voltage-doubled twins to work properly. The most
common complaint is blown diodes. The second most
common complaint is doubler cap failure. The third
most common complaint is poor performance. The results
I displayed on my web site should not be considered
typical.

For one thing, I am an experienced electronics
technician & troubleshooter. For another thing, I
spent years gaining practical experience with NST
coils before I started messing with MOTs. In other
words, I had a solid foundation to build on plus the
time, skills, and resources to work out the bugs.
Newbies who tackle a twin MOT supply for their
first-ever Tesla coil project are courting
disappointment.

Twin MOTs with doublers should be considered "the
power supply of last resort" for those who are simply
to poor to scrounge for NSTs, or for those who live in
countries where NSTs are nearly impossible to obtain.

Having let all that sunshine into your day, I'll take
a whack at your original question. I've gutted a large
number of dead ovens, and I can say with some
confidence that you may use your cap rating as the MOT
output. Since your oven came with a 2100WVAC (working
volts AC) cap, then it's a safe bet your MOT puts out
about 2100VAC. If you need more certainty, then apply
120vac wall current to your secondary and read the AC
volts on the primary. This will provide the exact
turns ratio. Current? Harder to say. You can short out
the secondary with an ammeter and read it, but this is
hardly a realistic load condition. My best advice is
not to worry about it too much. Even a smallish pair
of MOTs puts out ample current for hobby-level
coiling. If you can find another MOT like the one
you've already got, you're in business.

Best Regards,

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "Hydrogen18"
> <hydrogen18@xxxxxxxxxxxxx>
>
> Given the availability of of MOTs and the problems
> encountered with using
> the doubler I suggest you just try and find 3 more
> MOTs and make a 4 pack.
> You will need to remove the HV connection to the
> transformer core and
> connect it to a suitably insulated wire(ignition
> wire or neon sign wire) and
> then insulate that with epoxy. A fifth MOT with its
> secondary shorted can be
> used as a ballast. It isnt particularly difficult to
> wind a suitable
> inductor either.
>
> ---Eric
> ----- Original Message -----
> From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Friday, December 17, 2004 8:03 PM
> Subject: MOT supply
>
>
>  > Original poster: hue jass
> <chesscactuar@xxxxxxxxx>
>  >
>  > Hello! I am planning a new 4" coil, and i am
> limited on budget. I want to
>  > make one of Greg Hunter's dual MOT supply with
> doubler. I already have an
>  > MOT, but i dont have any idea how much voltage
> and current it can put out.
>  > Also, my microwave cap is rated .65 mF at 2100KV
> AC. I can find the
> diodes,
>  > caps, and resistors, but i need to know the if
> voltage of my MOT is enough
>  > and if the capacity of my cap is enough.
>  >
>  > thanks
>  > Blake
>  >



=====
Gregory R. Hunter

http:\\hot-streamer.com/greg