power supply for motor shield V.2.3

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phildob
 
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power supply for motor shield V.2.3

Post by phildob »

Hello,
I got a question about the Adafruit Motor Shield V2.3. I want to use it with two stepper motors but I'm not sure about the power supply. If I understand it correctly, the shield does no current regulation. But than I'm not sure about the voltage I should apply. Should I apply the "nameplate voltage"?

Regards phildob

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adafruit_support_bill
 
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Re: power supply for motor shield V.2.3

Post by adafruit_support_bill »

That depends. Manufacturers are not consistent in how they report the 'nameplate' voltage. Sometimes you need to read between the lines of the specs.

This is especially true of motors designed for use with current limiting drivers. Sometimes the voltage reported is the max voltage rating for the winding insulation. Sometimes it is the maximum holding current voltage which can be considerably lower.

If you post the specs for the motors you are looking at we can take a look.

https://learn.adafruit.com/all-about-st ... he-stepper

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phildob
 
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Re: power supply for motor shield V.2.3

Post by phildob »

Thanks for your support. I couldn't attach the datasheet to this post so here are the specs that I think are relevant:
Rated Voltage: 4.5V
Rated Phase Curent: 1.0A
Phase Resistance: 4.5 Ohm
Phase Inductance: 7.5mH

Would it also be possible to measure the current and increase the voltage until the wanted current is drawn?

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adafruit_support_bill
 
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Re: power supply for motor shield V.2.3

Post by adafruit_support_bill »

Based on the relatively low voltage and phase resistance, that motor is probably best driven with a current limiting driver. You could run it with the motor shield using 4.5v (It would probably be OK at 5v too) But you will get better performance using a higher voltage and a current limiting driver.
Would it also be possible to measure the current and increase the voltage until the wanted current is drawn?
That is what current limiting drivers do. It is not so simple to tack-on current limiting after-the-fact. You can measure current going into the shield, but even with just one stepper motor, you are driving two sets of windings. So it is not clear how much current is going into each winding at any given moment.

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