Re: interesting way to make 3phase power

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

Original poster: "Arpit Thomas" <arpit-at-inzo-dot-org> 

WOw, that's quite brilliant :)  Unfortunately its a bit expensive for me, 
Im still in high school. here we use a 240 volt AC supply single phase, and 
415 volts between phases on 3 phase. I want 3 phase, but it'll be really 
expensive to get. Just putting a 50 amp line for my tesla coil single phase 
would cost me 500 dollars, so that should give you an idea of how much more 
expensive 3 phase would be. SO I was thinking making it myself. I had 2 
options in  my mind, perhaps you can advise?

a. Use microwave oven transformers to step up 240 volts to 500 or so, then 
rectify  that. I could then use  mosfets connected to some sort of 
miroprocessor to produce 3 phase power.  Heres the problem I see 
though;  The rectified power will be, you know, rectified, not smooth dc. 
I'd need big capacitor banks.Expensive. ANother option would be a  large DC 
motor connected to a heavy flywheel, but thats complex, expensive, and 
where the hell do I get a big DC motor!?

b. Get an old car which can't pass rego, and with my angle grinder cut it 
between the front and back halves, and throw out the back half after 
rejoining the fuel tank. I could then theoretically put a whole lot of 
alternators connected by belts to the engine . ( I have no idea how id do 
this.). And the mother would be a trifle upset at me bringing a car into 
the garden. Plus cutting would be time consuming. Finally the alternators 
would produce high frequency power and not much of it :(

Final possibility might be to get the car and put it up on cinderblocks 
bolted to each other. I could then wind a huge generator of sorts and 
couple it to a wheel, when i wanted power i could just get in the car fire 
it up and put a few bricks oon the accelerator. THis is pretty impractical.

*********** REPLY SEPARATOR  ***********

On 17/04/2004 at 5:19 PM Tesla list wrote:

 >Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >
 >Honda has a very nice series of "inverter based" AC generators (they use a
 >DC generator driving a solid state inverter, so the motor can run at
 >varying
 >speeds depending on load).
 >
 >These can be paralleled to increase output power, so the solid state
 >inverter has some scheme to sense the load and stuff (maybe it measures
 >power factor?)
 >
 >Conceivably, one could build a little box that provides a low power phase
 >reference, then use 3 of the honda generators connected in Wye to make
 >120/208Y.  Perhaps a small 3 phase motor might be the way to provide the
 >phase reference for synch?
 >
 >These things are available in 3 or 4 power ratings (1kW, 2kW, and 3kW plus,
 >I think a 700W version)...
 >The 1kW version is around $700, the 2kW version is $900
 >They are very quiet, and you can rent them too...
 >
 >Actually, now that I think about it, you could probably use the much
 >cheaper
 >non-inverter style generators in the same way, except that syncing will be
 >a
 >bit more challenging (especially getting into sync at first)...  I see that
 >there are lots of (noisy) generators in the 5kW range for $500 or so.
 >
 >Hey, they just announced that outages this summer are very likely (no
 >investment in infrastructure, increasing population, improving business
 >climate), so you need to convince your significant other that an investment
 >of a few kilobucks will allow you to keep the refrigerator, a/c, and big
 >screen TV operating when things get toasty in June.