Re: a power supply question

I was curious about these steppers, so I took a quick look at the
numbers.

Briefly, if you figure volts divided by amps,... Check the motor
resistance. I would imagine it is NOT 38 ohms.

If you do a rough watts calc 65 volts times 1.75 equals 113 watts.

Since our resident Guru on the intracies of stepper power has offered
a rough average of stepper wattage in his Mystery Motors post, We
can assume that a single stack NEMA-23 is around 5 watts. super high
effency might add ?? 30%??

The nameplate is deffinatly NOT the STARTING point for the
calculations, but rather the maximum.

Assuming a high watt of say, 6 to 7, we could figure 7 watts, divided
by the 1.75 amps. That would put the motor at roughtly 4 volts.

4 volts / 1.75 amps = 2.28 ohms. much more likely.

That said, using the 5x mimimum voltage multiplier, the Xylotex will
fit the bill, but there is a lot of power left in the steppers that
will only be found by increasing the voltage.

Dave





--- In CAD_CAM_EDM_DRO@yahoogroups.com, "lum_l <lum_l@r...>"
<lum_l@r...> wrote:

> Hi All,
>
> I am sorry if this question has been asked before.
>
> I have purchased some steppers from Ebay, they are the
> powermax II , max 65 volt, 1.75 amp.
> (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=12577
> &item=3106027187) I also plan to use the xylotex driver board (3
> axis).
>
> My question is, what voltage and how many amp will require to
> drive these motors.
>
> The xylotex max voltage is 35 volts so I think I will need a supply
> that will give me 30 volts @ 6 amps. Am I correct ? If not can
> someone give the correct values. And does any one have a
> source for surplus supplies?
>
> Thanks for your help,
>
> Les