Re: Coil diameter choice criteria

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

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

At 02:50 PM 7/23/2003 -0600, you wrote:
>Original poster: "Dr. Resonance by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>
>
>
>The larger dia. you can tolerate with coupling more energy into the sec.
>coil.  As Tesla noted the larger dia. can develop higher potentials as the
>inductance goes up as the square of the radius of the coil.  That's one
>reason he used a 52 ft. dia. sec coil in his magnifier design at Col.
>Springs.


Then again, Tesla's materials technology wasn't anywhere near what we have 
available today, and, his figure of merit may not have been "spark length 
per input watt", so his optimization might have been for something else.


>For medium size coils with 4-6 foot spark a good size is 8-12 inch range.
Working backwards from 4-6 ft (48-72 inches) to power -> 800W-1800W
Using height = sparklength/3 -> sparklength/2 -> 16-24 inches, 24-36 
inches, and applying 4.5:1 for length -> 3.6"-5.3" , 5.3"-8"...


>With 7-12 ft. spark coil dia. in the range of 16-24 inches work good.

2.5kW - 7.2 kW


Maybe a guideline is diameter in inches should be twice spark length in feet?



>A height/dia ratio of 4.5:1 works good.  Also, calculate you sec. winding
>length to accomodate 1,400 turns of whatever gauge wire you are using.
>
>Dr. Resonance
>
>Resonance Research Corporation
>E11870 Shadylane Rd.
>Baraboo   WI   53913
> >
> > I was wondering if there is a standard criteria for deciding when one
>needs
> > to go to the next size larger coil diameter.  Assuming coils are at a 5:1
> > aspect ratio, is there a maxium something (voltage, or power, etc) for
>this
> > decision?