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Stepper very slow
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Stepper very slow

by rderimay on Sun Jun 14, 2020 9:27 am

I can not figure out why the stepper motors are spinning so slowly on my RPi.
Even when calling this with no sleep, I'll get maximum 30 rpm.

while True:
kit.stepper1.onestep(direction=STEPPER.FORWARD, style=STEPPER.INTERLEAVE)

This must be something pretty stupid...

Thanks !

rderimay
 
Posts: 7
Joined: Fri Jun 28, 2013 8:20 am

Re: Stepper very slow

by adafruit_support_bill on Sun Jun 14, 2020 10:57 am

What stepper are you using?

adafruit_support_bill
 
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Re: Stepper very slow

by rderimay on Sun Jun 14, 2020 11:10 am

adafruit_support_bill wrote:What stepper are you using?


This is a Nema 17 stepper from LDO

rderimay
 
Posts: 7
Joined: Fri Jun 28, 2013 8:20 am

Re: Stepper very slow

by adafruit_support_bill on Sun Jun 14, 2020 11:20 am

NEMA-17 is just a frame-size designation. It tells us where the bolt holes in the faceplate are. It doesn't tell us anything about the electro-mechanical properties of the motor. Please post a link to the specifications for the motor you are using.

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Re: Stepper very slow

by rderimay on Sun Jun 14, 2020 12:10 pm

This is what I found :

https://cdn.shopify.com/s/files/1/0887/ ... R_RevA.pdf

On the left bottom corner, hope you find what you are searching for :-|

rderimay
 
Posts: 7
Joined: Fri Jun 28, 2013 8:20 am

Re: Stepper very slow

by adafruit_support_bill on Sun Jun 14, 2020 12:35 pm

Unfortunately, that motor is not compatible with the motor HAT or Bonnet. It has a phase resistance of just 4.1 ohms/phase and a current rating of 1A/phase - suggesting that it was designed for use with a current-limiting driver like the DRV8833. https://www.adafruit.com/product/3297

Since the TB6612B drivers on the motor HATs and Bonnets do not have current limiting, you would need a supply voltage of 4.1v or less to avoid overloading the motor. (And any voltage over 4.9V risks overloading the drivers.) However the minimum operating voltage for the drivers on the HATs and Bonnets is 4.5v.

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

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Re: Stepper very slow

by rderimay on Sun Jun 14, 2020 2:13 pm

Many thanks !

rderimay
 
Posts: 7
Joined: Fri Jun 28, 2013 8:20 am

Please be positive and constructive with your questions and comments.