Re: Xylotex / RapidSyn/ Power Supply help?

Hello,

You aren't going to limit the voltage down to 2.58. You will let the
drive limit the current to the motor. It will use PWM to keep the
motor current at the correct level. A higher motor supply voltage
allows the current in the coils to build up faster. The faster it
builds, the faster it reaches the proper level, which is where you
reach rated torque.

Mariss of geckodrive.com suggests having the power supply voltage
between "3 to 25 times the motor's rated voltage". Thus for your
motor, that's 7.5V to 62.5V. The Xylotex drive MAXIMUM PEAK voltage
is 35V. The suggested running peak is 90% of that, or around 30V. I
find 24V to be a good choice for two reasons: they are alot more
available than a 30V supply, thus cheaper, plus they give a wider
voltage safety margin; motor decel BEMF generally isn't going to be a
big problem. A 12V supply will work, but will not give you the
performance that a higher voltage will (especially if you are trying
to step at high rates) (even more so if you use the unipolar motor in
6-wire full winding (series) mode.

See:
http://www.geckodrive.com/ycom/documents/C163R16_power_supplies.pdf

Jeff
www.xylotex.com


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "volitan712003
<volitan@o...>" <volitan@o...> wrote:

> Thanks for all the excellent responses!
>
> If I understand correctly, stepper motors are "current" driven,
> rather then "voltage" driven. However more voltage will give you

more

> RPM's. But if I'm going to limit the voltage on the driver down to
> 2.58 volts anyway, couldn't I use a 12v power supply? I have one

here

> thats 12v and 8amps. I'm asking before I hook it up, because I'm

not

> sure I understand completely yet.
>
> If I'm using 2.58 volts and 1.79 amps, then even if all three

motors

> turn at once then the most they will draw is 7.74 volts and 5.37
> amps, pretty well below the limits of the power supply I have here.
>
> Am I thinking about this the right way?
>
> Thanks!