[satguy]

Hi
Im planing on ordering a nema 17 , 74 oz bipolar motor with the following figures:
Rated @ 2 amps
Resistance per phase: 1.2 OHMS
Connection: 4 wires

My question is will a 12v power supply rated at 2 amps output be enough to run this motor.
According to the geckodrive website to get the voltage of the stepper motor you simply multiply (amps X resistance)
so in this case this would give me (2 x 1.2 = 2.4Volts)
Then they reccomend "The power supply voltage should be
between 3 to 25 times the motor’s rated voltage."

so in this case anything between 9-12V @ 2amps should be plenty right? the motor is only spinning at a low rpm for a few revolutions.

im thinking of using a simple 12V power supply to run the motor. something maybe like this:
http://cgi.ebay.com/Genuine-D-Link-S...3A1%7C294%3A50

this will not be used to run a CNC but to drive a linear rail via a pulley system.

is there any problem with what im thinking of doing? will the motor performace suffer? can i expect anywhere near the specified torque of 74oz?

sorry for the long multiple question but this stuff is really confusing for a novice.

thanks

[ger21]

Are you going to use a Gecko drive? And how fast do you want it to spin?

[satguy]

no im going to use a all in one controller/driver built by www.electrozoneuk.com

the driver/controller im going to use is rated at:
Drive Current 2 Amps
Power Supply 9V to 26V D/C

so im hoping to use the same power supply for the motor and the driver if that is possible to keep the setup as simple as possible.

the stepper is only going to spin at a slow pace of approx 40-50 rev per minute for approx 2-3 seconds only. its just to move the linear rail left and right at a press of a button.

[Spiv]

It should work just fine for the speeds you're running. The usual problem with needing very high voltage is to offset coil induction time (IE higher voltage allows coils to switch faster in the motor). If you're running a lower voltage but supplying enough current (looks like a current controlling board you're using) then you lose torque with speed because the coils are not being fully charged/discharged from step to step.

Lower RPM = closer to rated torque, even if you aren't pumping crazy voltage into it.

[satguy]

great Spiv. thank you thats what i wanted to hear.
can you please also tell me if using a switching power supply like the one on the link i have put above will cause problems. I am not too educated about the different types of power supplies. Is a switching power supply ok to use?

[Spiv]

A switching supply should be ok to use. There's a potential that it could be too noisy for your controller, but a lot of people use old computer supplies as sources. There's also a chance that the supply has poor ability to deal with the varying loads of a stepper and could be damaged in time. A simple solution would be to drop a large capacitor in line to help stabilize the loads.

[satguy]

thanks Spiv you have cleared things up for me. i appreciate it