Stepper motor speed problem.

[shikha829]

Hello,

I have stepper motor with following parameter, can someone help me in finding out why my motor did not get speed.
what is the minimum power supply requirement for this config ?
Type : Bipolar
Angle : 1.8deg
Rated Voltage : 4.5
Current/Phase Amp : 3
Resistance/Phase : 1.2 Ohm
Inductance/Phase : 3.8 mH
Holding torque : 25 kgcm
Rotor Inertia : 500 gcm.

I tried rampup using 12V power supply but not get enought speed.

Thanks in Advanced.

[Richards]

If you use Geckodrive stepper drivers, a 3.8mH motor will work well with a 60VDC power supply. I use the G203v stepper drivers, but any Gecko stepper driver will work, even the G250/G251. The G250/G251 drivers are limited to 50VDC, but 50VDC would still give you very good speed.

[KenC]

Check this out. http://www.mechmate.com/forums/forumdisplay.php?f=14

[shikha829]

Thanks for your reply, i now have some understanding about this. how much voltage needed to get 25Kgcm torque ? is there any calculation ?

[Richards]

The motors are rated at 25Kgcm HOLDING torque. That usually means that 25Kgcm is also their maximum torque. Depending on the motor, holding torque does not depend on high voltage. Speed requires high voltage. With my Oriental Motor stepper motors, I can generate maximum holding torque at 50% of the voltage required for high speed, as long as 50% is at least 15VDC or 24VDC (depending on whether I'm using G203v stepper drivers or G202 stepper drivers).

You need to look at some torque charts for your motor. Most motors show high torque when they move slowly and then a gradual drop in torque until the speed enters the "knee" portion of the curve. That's when torque suddenly drops off. For best results, you need to keep speed below the "knee" drop-off speed.

I've run some little size-17 motors at more than 6,000 RPM without a load, but even after a short 3-5 minute test, they were too hot to touch. That's what happens when a motor is run past the knee portion of the curve, it loses torque and generates a great deal of heat.