Author Topic: Stepper motor speed control using a pot  (Read 4067 times)

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Offline dsesmgTopic starter

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Stepper motor speed control using a pot
« on: September 23, 2009, 06:24:49 PM »
Hi, I am trying to control the speed of a unipolar stepper motor using a potentiameter.
The specification of the stepper motor is as below.

- 1.8°/Step
-Operating voltage : DC 4V
-Holding Torque:1.6Kgf-cm
-Detent Torque:120gf-cm
-Rotor Inertia:38g-cm

I just need this stepper motor to turn one direction and hopfully, I need to increase or decrease its speed by adjusting a potentiameter.
I once arranged a stepper circuit using two ULN2003 chips to cope with the above stepper motor before. I used Darlington transistor array for a unipolar stepper motor in this tutorial.
Since the current of the stepper motor is almost 1A, I parrelelled two ULN2003 so that the chip could cope with the motor's current needs.

The circuit diagram of the stepper motor is this.
Could you advise me where and how can I put a potentiameter?

Offline paulstreats

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Re: Stepper motor speed control using a pot
« Reply #1 on: September 23, 2009, 07:37:37 PM »
you cant directly affect the speed of a stepper motor by limiting the current or potential with a Pot. Sorry.

If you are using a microcontroller to control the stepper, then you can read in the Pot value and adjust the ste speed according to the analog reading

Offline RoboGeek

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Re: Stepper motor speed control using a pot
« Reply #2 on: September 24, 2009, 09:06:37 AM »
You can use any typical "stepper motor driver" these accept step and direction inputs.

Then connect your pot to a 555 timer so it makes an "555 adjustable frequency oscillator", then just attach the oscillator output to the STEP input of the stepper motor driver.


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