[Prev][Next][Index][Thread]

Re: Direct current coils

My last post clerified my error in voltage. At 4000rpm it is a  400 amp
30v DC
generator...
I hope to use a steam turbine to turn it.  I also need plans for a very small
coil for my sons science fair project.

   ( I am a total novice in coil design) Must you convert to AC ?

>
>
> Running from the "Volt Police" by any chance? (Folks I'm not kidding in
> the slightest here!).
>
> Get an alternator normally used at 3600 RPM on a small Brigg's &
> Stratton or similar industrial/lawnmower type gasoline engine and drive
> it from a modified car starter motor from a huge detroit automobile V8
> of yesteryear.  Use this MG (Motor-Generator) set to power your
> traditional Tesla coil. The idea is to get the starter motor to spin the
> alternator at as close to 3600 RPM under the load as possible by
> suitable pulleys         or gears.  Don't expect to run much more than
> 60
> seconds and then a loooong rest or you can kiss your starter goodby.
> Solid state power perverters won't likely survive in this application
> due to damaging transients produced by the TC load, but a good old MG
> set has half a chance, unless you live in Colorado Springs, the date is
> circa 1899, and your name is Nikola 'something'.
>
> If you are not in fact running from a state empowered electrical
> inspection/liscencing organization, and merely trying to operate off a
> mobile source like a car battery, you will do better by upping your
> battery voltage to 24 volts and using a modified diesel truck or
> aircraft starter motor to turn your alternator.  The exact frequency is
> determined by the motor speed under load and is not really critical, as
> long as it is at 60 Hz or maybe two or 3 octaves higher at the most,
> assuming you have good steel in your transformer.  I can't say how well
> this works with a neon sign xfmer, except that coils driven by them work
> just as well off a portable 115 volt, 60 Hz portable gasoline powered
> genset as they do off the mains, as long as the genset is big enough.
>
> You mentioned 12 volts -at- 400 amps.  That's 4800 watts, or about 4 kVA
> after losses in an MG set conversion to AC.  This is in the realm of a
> small pole transformer (~5 kVA) which should have better steel for
> higher frequency operation than a bank of junky NST's.  I'd opt for a
> small pole pig myself in this case.
>
> Robert W. Stephens