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# Re: phase help

```In a message dated 10/28/99 5:25:28 AM Central Daylight Time,
tesla-at-pupman-dot-com writes:

<< Original Poster: Russell Keiner <oreo22-at-bellsouth-dot-net>

>>>>>> when you talk about phase, like " its not in phase" or that is a
(IT'S)
"three phase transformer"    what does that mean??<<<<<<<<<

Russell,
re PHASE:

You might want to start by looking-up the basic meaning(s) of the word in any
dictionary. Proceed from there to an encyclopedia article on alternating
current generators.

Imagine a simple loop of wire rotating between the poles of a magnet. An
alternating current is produced and may be removed from the loop by placing
brushes at the ends of the loop to supply an external circuit. One complete
rotation of the loop thru 360 degrees is one cycle of AC, and the number of
cycles per second is the frequency. A graph of the
voltage output of the generator produces a sine wave when you graph voltage vs
the angle
of rotation in degrees. The points of maximum output occur when the loop is
moving
perpendicular to the magnetic field at 90 and 270 degrees simultaneously. The
sine curve at 90 degrees is positive. At 270 degrees the curve is negative.
So as the loop turns,
the polarity on one side of the loop goes from zero to max and back to zero
in 180 degrees. Then the same side of the loop moves down past the opposite
magnetic pole as it rotates from 180 degrees to a max negative at 270 degrees
and back to zero. that's one complete rotation or one cycle. One complete
cycle on the graph equals 360 degrees.  This is the graph for a single-phase
generator. If you place another loop of wire designed to rotate
simultaneously with the first loop but spaced perpendicular or 90 degrees to
the first loop, you will have added a second phase because the voltages in
each loop will reach their maximum points 90 degrees out-of phase from
eachother.

This explanation requires diagrams. I surely could not understand what I have
just written
without diagrams. There are many experts on the Tesla list who will be glad
to help you.
If you will tell us how old you are we will be able to refer you to many
books on the subject
that start at the level of the good question you have asked. Again, I urge
you to start out with the dictionary and encyclopedia articles. Go to the
library and talk to your teachers.

Cheers,
Ralph Zekelman

```