Re: getting three phase power

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

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

I'd also try doing a search with your favorite search engine for the term

"six pulse rectifier"

You'll get a whole raft of hits which will show you wiring diagrams, etc.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, January 20, 2001 3:24 PM
Subject: Re: getting three phase power


> 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
> > >
> > >
> > >
> > >
> > >
>
>
>
>