RE: Explain 3 Phase

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

Original poster: "Tuite, Tom by way of Terry Fritz <twftesla-at-uswest-dot-net>" <TTuite-at-ALLEGROMICRO-dot-com>

Ack, I am afraid I lost some of the replies to this post so forgive me if I
re-cover some ground.  I believe the power companies transmit their power
(in the pre-house power lines) in three phase, which is where that is coming
from.  It is correct that the wall sockets in most homes are +-120 V or two
120 volt signals 180 degrees out of phase, how ever you want to call it (
don't make me break out vectors of the imaginary/real planes :P ).  Anyway,
if you need three phase I know some easy ways of obtaining this from wall
sockets so let me know :)

Tom T.




> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Friday, April 27, 2001 4:08 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Explain 3 Phase
> 
> 
> Original poster: "Eric Davidson by way of Terry Fritz 
> <twftesla-at-uswest-dot-net>" <edavidson-at-icva.gov>
> 
> Hi All,
> 
> One more time.....  The electrical service supplied to 99.9% 
> of American
> homes is single phase, 120/240 volt, 3 wire service.  Single 
> phase means ONE
> phase...period....not 2 phases 180 degrees apart.  The 
> service enters the
> house via a cable comprising two insulated (hot or line) 
> conductors wrapped
> around an uninsulated, grounded, neutral conductor.  The 
> neutral conductor
> is connected to the midpoint of the secondary winding on the 
> distribution
> transformer on the pole or the pad and connected solidly to 
> ground.  The
> voltage between the two line conductors is 240 and between 
> either line and
> neutral is 120.  The function of the neutral conductor is to carry the
> unbalanced portion of the load.  If you had only identical 
> 100 watt, 120
> volt light bulbs as the only loads in your house, and they were evenly
> distributed so the same number of bulbs ran on each line 
> conductor, the
> neutral conductor would carry no current.  The two line 
> conductors are of
> opposite POLARITY compared to the neutral conductors.  The 
> same situation
> exists on a Y connected 3-phase bank.  The neutral is 
> grounded for safety
> reasons.  One of which is that the maximum voltage from line 
> to ground in
> your home is 120 volts.  So, even if you stuck your finger in 
> a 240 volt
> dryer outlet, you would feel a 120 volt shock, provided you 
> had good contact
> with the ground.  To experience 240 volts you have to stick 
> both fingers in
> the outlet.  DON'T TRY THIS!  Hope this helps.  Coil safe!
> 
> Eric
> edavidson-at-icva.gov
> 
> 
>  ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Friday, April 27, 2001 8:55 AM
> Subject: Re: Explain 3 Phase
> 
> 
> > Original poster: "Millipede by way of Terry Fritz 
> <twftesla-at-uswest-dot-net>"
> <millipede-at-carolina.rr-dot-com>
> >
> > 3 phase power in the US is  three 60 hertz (cycles per 
> second) signals set
> > at 120 degrees apart. Thus when cycle A is peaking, cycle B 
> is 120 dgrees
> > behind it and cycle C is 240 degrees behind A. Your house 
> power is usually
> > supplied with 240 volt main...which is actually two 120 
> volt signals that
> > are 180 degrees oout. So when A is peaking positive, B is peaking
> negative.
> > THerefore you have a difference in voltage of 240 V. Your 
> wall sockets
> have
> > one of the wires from the 240 paired with a neutral wire to 
> get you 120V.
> So
> > basicly, you are gettin one phase. You can do this with a 3 
> phase system
> > also.
> > Hope this helps.
> > Robert
> > ----- Original Message -----
> > From: Tesla list <tesla-at-pupman-dot-com>
> > To: <tesla-at-pupman-dot-com>
> > Sent: Sunday, April 22, 2001 7:07 AM
> > Subject: Explain 3 Phase
> 
> 
> 
>