RE: [CAD_CAM_EDM_DRO] current set resistor

Yes, no resistor between 11 & 12 and you will have the Gecko G201/210
set to the maximum 7 amp rating. Ran one that way on Bridgett when I was
still playing with the stock stepper motors. As the resistance between
the terminals reduces so does the maximum current the drive will put
out.

Tim
[Denver, CO]

> -----Original Message-----
>
>
> Hi,
>
> In the unipolar drives, the current limiting resitor is used to limit
> the current to the motor when back emf is zero or very low. Knowing
> this it is easy for one to calculate what resistor to use given the
> coil resistance.
>
> I hope to understand the use of the current set resistor for the
> gecko stepper drive. Is the current set resistor put there to "sense"
> when current need to be chopped off or something? Understanding it
> will make one more confident in calculating a suitable resistor to be
> used with a particular motor, rather than just plugging specs into a
> given formula without understanding the formula
>
> R = (47,500 * I)/(7 - I)
>
> It would help to know where the 47,500 and the 7 came from. What
> should one do, for example, if the motor rated current is 7 amp (R =
> infinity) keep the teminals 11 and 12 open?
>
> Thanks
>
> Peter
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/