Re: fickle y-axis

Hi Peter,
Remeber, the descriptions I was giving was for your motor without
the second phase(broken wire). With the diagram shown below with A
as the second (presently un-energized-full step mode) phase, to get
clockwise rotation, The A on the RIGHT would be energized NORTH,
while the (A#) on the left would be energized SOUTH. The present N
(which I've labeled B, and the present S, which I've label B#) would
be deenergized.

> ......................B.........................
> ......................N.........................
> ................................................
> ................................................
> ......................S.........................
> ......................|.........................
> ......................|........................
> ......................|.........................
> ......................|.........................
> ......................|.........................
> ......................|.........................
> A#....................X........................A
> ......................|.........................
> ......................|.........................
> ......................|.........................
> ......................|.........................
> ......................|.........................
> ......................|.........................
> ......................N.........................
> ................................................
> ................................................
> ................................................
> ......................S.........................

........................B#........................

>

to get:

> ......................B.........................
> ................................................
> ................................................
> ................................................
> ................................................
> ................................................
> ...............................................
> ................................................
> ................................................
> ................................................
> ................................................
> A#-S..N---------------X-------------------S..N.A
> ................................................
> ................................................
> ................................................
> ................................................
> ................................................
> .................................................
> ................................................
> ................................................
> ................................................
> ................................................
> ................................................

........................B#........................

The way we made the origianl A (on the right hand side) turn from
nothing to NORTH is by running current through the coils. A unipolar
motor has two set of coils. If current is run the one set, the pole
will be NORTH. If the current is run through the other, the pole
will be SOUTH. If current is run through both you are in trouble.

With a Bipolar motor there is essentially only one coil per pole (two
per motor, in a two phase motor). Run the current one direction
through the coil and your will get NORTH (at a given end of the
pole), run it through the other direction and you will get SOUTH.
Changing from NORTH to SOUTH (on a given pole) simply entails
swapping the + and - power input leads to the opposite side of the
coil to get the current to flow the opposite direction, thus reverse
the magnetic polarity.

Better?

Jeff
http://www.xylotex.com