Re: 6 wire motor running bipolar

Thanks Jeff. So, what your saying is, if I'm going to use 6 wire
motors, I'll get the best performance if the motor's unipolar rating
is as close to 2.5a , and the bipolar half winding will have the same
rating. Will I get the unipolar rated torque, or less, or more? Sorry
for all the questions, just want to buy the best motors to use for
your driver. I can get a good price on the vexta's, so it looks like
the PK268-2A will work better, as it's rated at 2 amps with more
torque. I'm looking for the most torque in the 200-300rpm range, if
that helps. Thanks again,

Gerry













--- In CAD_CAM_EDM_DRO@yahoogroups.com, "jeffalanp" <xylotex@h...>
wrote:

> Hi Gerry,
> With the Xylotex drive, and 6-wire motors, you have two

choices.

> Bipolar series winding, and bipolar half-winding.
> With bipolar series winding (end to end, center tap unused),

when

> running in microstepping mode (preferable), you actually want to

use

> HALF the rated unipolar rating, as you will be driving DOUBLE the
> number of wires turns. The probelm with this winding mode is that
> you increase the inductance, thus the time it takes to fully

energize

> the coils. Becasue of this, you can end up loosing torque at

higher

> step rates
> With bipolar half winding you use one end and the center tap.

You

> would then run the drive at full amperage (2.5A/phase). Although
> this is not quite the full rating of the motor, you can still get
> good performance at lower speeds, and MUCH better performance than
> series winding mode at higher speeds.
> You never want to run a motor at more than it's specified

amperage

> rating, but almost always run it at higher than the specified

voltage

> rating. The most common voltage used for the Xylotex drives is 24V.
>
> Jeff
> http://www.xylotex.com
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "notoneleft" <ger21@c...>
> wrote:
> > I'm building a small CNC router and I have a question about 6

wire

> > steppers. I plan on using a Xylotex driver. I've been doing a lot
> of
> > research, as this is my first CNC project and I've come across a
> > conversion chart for unipolar and bipolar ratings. I'm looking at
> > some Vexta PK266-03B motors, rated at 3amps 2.3V unipolar. If

what

> > I've read is correct, when running these on the xylotex

board "end

> to
> > end", do the motors then actually draw 2.1 amps @ 3.22V? And do I
> see
> > a 40% increase in torque. Thanks.
> >
> > Gerry