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[on:]

hi

i bought arduino uno, motor shield and stepper motor 1.8 degree. can i reach high RPM (about 5000 - 7000 rpm) with this motor shield? if yes how?
i dont need tork.

thanks for your answer  

[Reply #1 on:]

i bought arduino uno, motor shield and stepper motor 1.8 degree. can i reach high RPM (about 5000 - 7000 rpm) with this motor shield? if yes how?
i dont need tork.

Well, a stepper motor is used for precise steps, not for fast rotational speed. I don't specifically know the answer but I would think you don't want to use a stepper motor for those fast speeds.

[Reply #2 on:]

i have read if change the pwm frequency motor RPM is change. how i can set the pwm frequency?

[Reply #3 on:]

hi

i bought arduino uno, motor shield and stepper motor 1.8 degree. can i reach high RPM (about 5000 - 7000 rpm) with this motor shield? if yes how?
i dont need tork.

thanks for your answer  

Not a chance.

Even the fastest constant-current stepper motor drivers (typically running at 75V) couldn't overcome the back EMF at those
speeds.   Perhaps upto 3000rpm is achievable with this technology but that would require low inductance, low resistance
stepper motor windings.

Without constant current (chopper) drive then 200--300 rpm would be pushing it.

Insert Quote
i have read if change the pwm frequency motor RPM is change. how i can set the pwm frequency?

No, that's not stepper motors.  Normally PWM controls average voltage to a DC motor.  You can only PWM steppers if running them
with constant voltage drive, which means only slow stepping - the PWM allows you to reduce current drain and heating when the
motor is stationary, not much more.

The kind of stepper motors designed for high-speed high-torque operation might be rated about 5A, 2V (0.4ohm) windings - utterly
impractical to drive from PWM.

[Reply #4 on:]

If you are looking for high RPM AND a stepper interface you should look into BRUSHLESS AC DRIVES. they come in sizes from 30W to huge and are more costly than steppers.

Steppers are for lower RPMS, and are more often used for positioning.