Re: getting three phase power

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

Original poster: "bob golding by way of Terry Fritz <twftesla-at-uswest-dot-net>" <yubba-at-clara-dot-net>

Hi Jim,
    A thought comes to mind. I have a shed full of MOT's ( no two the same
of course) and a three
phase supply 415 volts 50 hz 30 amps per phase.  Could I run three pairs of
MOT's (2 in series
across each phase) feeding into a 3 phase rectifier. Don't know where to go
after that.  Help.
Does this look as if it might go somewhere?

cheers
bob golding

Tesla list wrote:

> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<jimlux-at-earthlink-dot-net>
>
> Actually, if I were running a DC coil, I'd much rather run it off a
> unfiltered 3 phase rectifier, or with a bit of clever transformer wiring, a
> 6 phase rectifier, than off a big single phase with a monster filter.  The
> stored energy in the filter is a real problem: one flashover and your
> primary circuit just became a electroforming apparatus or an exploding wire
> or both, none of which is particularly pleasant.  Polyphase rectifiers are
> neat, because you get low ripple with no stored energy.  Turn the switch
> off, and it's dead.
>
> 3 phase doesn't necessarily imply high power (although higher powers do
> imply three phase, or extreme annoyance from the power company for screwing
> up the balance)
>
> If I had three phase power here, particularly 120/208Y, I'd definitely run
> three NSTs in parallel on separate phases as a DC coil, rather than running
> them all on one phase.
>
> Likewise, if one is running, say, 5-10 kVA (and there are a fair number of
> folks on the list doing just that), it's a lot easier to find componentry to
> handle the 15-20 amps per phase, rather than handling the 50 amps you'd need
> for single phase.  When you start getting over 20-25 amps, everything gets a
> LOT more expensive: switches, variacs, fuses, fuseholders, plugs and
> sockets, etc.  There's a good reason why three phase is popular for loads
> over a few kW, especially if you start pricing good  plugs and receptacles
> to handle 10 kVA, (i.e. not stove/dryer plugs which are really designed to
> be plugged or unplugged a few dozen times, at most).
>
> And, it's not necessarily thousands of dollars to get three phase power
> installed.  It depends on the rules, what services are already available,
> etc. In my case, the (3 phase) distribution transformer is about 10 feet
> from my service entrance panel on a concrete pad.  It might be a few hundred
> dollars, or even a thousand, but probably not ten thousand dollars. It
> wouldn't be the first thousand dollars I had frittered away on something
> seemingly pointless (at least, so my wife would claim).
>
>  The point is to not reject out of hand the possibility of three phase power
> (which comes up every few months on the list).  Also, one shouldn't just
> blindly take the word of the weenie who answers the customer service phone
> and tells you "it can't be done".  These days, it's easy to actually go look
> up the rules (an advantage of regulated utilities) and find out what the
> REAL requirements are.  Then, when you call, and the customer service rep
> says, it's against the rules, you can ask, "which rule, specifically?" and
> maybe you can work out a way to do it, if it is sufficiently valuable or
> important.
>
> Note also that a TC doesn't inherently require any particular type of power.
> Sure, most folks start with single phase AC power, because it is easy. But,
> there is a lot of interest in DC, or rectified AC, and, in fact, prior to
> electromagnetic accelerators, one of the ways to generate high energy X rays
> (1 MeV) was with a "resonance transformer" which used 3 phase power and some
> clever saturating inductors to excite the inductors and capacitors at 180
> Hz.
>
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Friday, January 19, 2001 5:21 PM
> Subject: Re: getting three phase power
>
> > Original poster: "Eric Davidson by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <edavidson-at-icva.gov>
> >
> > Hi All,
> >
> > Can anyone give me ONE good reason why you would need/want to power a
> Tesla
> > coil with 3-phase?? All this talk of trying to get 3 phase service to your
> > home, telling the power company you have a 10 hp motor you need to
> power...
> > stuff like that...gimme a break....a Tesla coil is a decidedly SINGLE
> phase
> > device.   You may argue that creating the DC for a VTTC might be a little
> > better using 3 phase, but even that would hardly justify the $THOUSANDS$
> of
> > dollars needed to bring 3 phase service to the average home.  IMHO we
> should
> > let the 3 phase discussion thread die on the vine, there is ample fodder
> for
> > discussion in tweaking, optimizing and theorizing about our single phase
> > coils.  Coil safe
> >
> > Eric
> > edavidson-at-icva.gov
> >
> >
> >
> >
> >