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Author Topic: Stepper Motor and Volts  (Read 1878 times)
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I have a stepper motor and it does not seem to turn with the load I have put on the shaft. Its not much, but the only question is, does pushing more volts to the stepper make it able to handle a heavier load or turn heavier things?
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Pushing more current will make it handle a heavier load, or be able to turn faster for the same load.

Applying more voltage will cause more current to flow, but you must be careful not to exceed the rated voltage of your motor driver (and I'd recommend staying at least a few volts away from it). Of course, do not exceed the current rating of the motor either.

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Thanks for that info. I definitely know I have to be careful not to exceed the motor and controllers specs.

Appreciate the response.
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I am wondering if might need a different stepper motor. I have put 12 volts to mine from a car battery and it still does not seem to be able to turn the shaft when I have the load I put on it. Which all that is attached to the shaft is a gear like device weighing less than an 4 grams and then I attach about 1 ounch of aluminum sheet that is about 1 foot long and about an inch wide.

Could I possibly need a different stepper and or more juice. The stepper I am using is the following: http://www.sparkfun.com/products/9238
« Last Edit: November 21, 2010, 05:05:18 pm by tarrigo » Logged

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I have put 12 volts to mine from a car battery and it still does not seem to be able to turn the shaft when I have the load I put on it.
I presume that you are not really connecting the car battery directly to the stepper motor. You aren't, are you?
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No no, I am hooking up the car battery to the stepper controller board.
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How are you telling the stepper motor to step? A 12 volt car battery should be providing more than enough current to move that stepper motor, even with the load you have on it (assuming the weights, in different units are indeed accurate).
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Well, it moves the stepper without a problem. It just doesn't seem to have any strength. I can stop it just with a pinch of the fingers.

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That motor is rated for less than 4 watts of power (12 volts times 0.33 amps) so it's not going to have much torque. At best it should produce something like 40 oz/inches of torque at 100 RPM.

You can find some good information on how to estimate the size of motor you need at:
http://techref.massmind.org/techref/io/steppers.htm#Estimating but you will need to measure the actual torque you need or at least have some idea of how many pounds you want to move and how fast you want to move it.

What sort of driver are you using? E.g. what drive electronics are between the Arduino and the motor?
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These two links below are what I am using.


Stepper Motor
http://www.sparkfun.com/products/9238

Stepper Controller
http://www.sparkfun.com/products/9402
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The sparkfun controller has an adjustable current limit. It may be set too low for your motor. You need a meter to adjust it. See the procedure in the user manual.
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