Re: MOT coil does not light

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

Original poster: Finn Hammer <f-h-at-c.dk> 

Aron,

This is no thing to mess around with, just shorting terminals together to 
judge if things are right.
Measure is the way to go.

If you have not got a variac to ramp voltages up with, take advantage of 
the voltage step-down ability of the transformers, so that you finish the 
connections on the secondary`s and then apply 110 Volts to them and measure 
the voltage on the primary windings. Much safer.

MOT`s are arranged symmetrically around a common grounded point, which 
includes the cores of the 2 center MOT`s, and the centerpoint of the 
secondary windings. From this centerpoint, the secondary`s fan out to eash 
side in series, whereas all four primary windings are tied together in 
parallel, spanning across this centerpoint, but not connected to it 
electrically.

Make up each side separately, then finally hook them up together.

There is a voltage stepdown ratio of 2000/110=approx 1:20 or 1:40 for the 2 
MOT`s in series.

If you apply 110 volts to the 2 secondary`s in series, you will get 110/40= 
approx 2.5 volts on the primary`s.

Now parallel them. either you get very close to 0 volts or you get ~2.5 
volts. Go for the connection that produces ~2.5 volts.

Repeat this procedure on the other side of the MOT-Pack.

Finally, connect the MOT`s secondary`s at the centerpoint, and apply 110 
volts to it.

The stepdown ratio is now ~80:1, so you should find the connection, where 
you get ~1.25 volts across the primary`s, rather than close to 0 volts.

I`ve done this, and I tell you: you can mess around with this phasing 
buisness for ages untill you analyze the situation and measure.
Then it takes 5 minutes.

Stop whining about getting your fingers into oil. You put it there, so set 
it right and move on. (been there, done that :-)

Hope this helps, Finn Hammer

Tesla list wrote:
>Original poster: "Aaron Aab" <striker754-at-earthlink-dot-net>
>Alright well......I tried switching around the HOT hookups on the MOTs and
>some interesting results...
>How I had it originally, each side (2 transformers) to each 110v, made a
>nice spark, but had to be touched to start the arc.
>2 inside transformers to 110v and the 2 outside transformers to 110v created
>just a small spark when the HV leads were touched
>one inside and one outside to a 110v and the other inside and outside to a
>110v yielded the same small spark.
>Any ideas? I really am hoping to get a definate answer so I don't have to
>mess around in that darn oil.
>
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Monday, January 26, 2004 8:01 AM
>Subject: Re: MOT coil does not light
>
>  > Original poster: "Arpit Thomas" <neko4-at-dodo-dot-com.au>
>  >
>  > I think 1 or 2 of your transformers maybe connected the wrong way around,
>  > if you knwo what I mean, so the peak of the sine wave created from one
>  > cancels the trough created by the other.... just a thought. Try hooking 2
>  > in series, not 4, and seeing if you can get an arc with them. If not, try
>  > flipping the 'polarity'  of the output of one. THen see if you get a
>bigger
>  > spark. DO this to the other pair, then put the pairs together, treating
>  > each pair like a single transformer like before.
>  >
>  > *********** REPLY SEPARATOR  ***********
>  >
>  > On 25/01/2004 at 10:24 PM Tesla list wrote:
>  >
>  >  >Original poster: "Aaron Aab" <striker754-at-earthlink-dot-net>
>  >  >
>  >  >First of all my coil is,
>  >  >
>  >  >15 turn primary, made of 6ga wire, spaced 1/4 inch apart.
>  >  >30.5" x 6.25" secondary, 7X24" toroid
>  >  >
>  >  >string of 6 caps and a string of 5 for a total voltage of 10kV and 0.055
>uF
>  >  >
>  >  >I originally was running the 9kV/60Ma NST on it until I could get these
>  >  >wired up.
>  >  >
>  >  >The MOTs are wired in series with the center 2 MOTs hooked to the core.
>  >  >They are covered in non detergant motor oil. Trying them off the coil
>  >  >without oil, I couldn't draw an arc without first touching one lead to
>the
>  >  >other then pulling it away. Thus, the spark gap wont jump unless they
>are
>  >  >almost touching.
>  >  >
>  >  >When the gap does light, nothing happens. I tried both my blower gap
>made
>  >  >from a plastic PVC tee, and my 2 bolts design
>  >  >
>  >  >Any ideas? I thought MOTs were supposed to be almighty and create big
>  >  >sparks...LOL
>  >  >
>  >  >Aaron
>  >
>  >
>