28BYJ-48 12VDC stepper motor number of steps seems to be incorrect

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sridhar_rajagopal
 
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Re: 28BYJ-48 12VDC stepper motor number of steps seems to be incorrect

Post by sridhar_rajagopal »

Thanks for checking, Bill! That is a bit bizarre! Your math seems right - the difference between this and the other link I'd posted (with a gear ratio of 63.684) is the idler (22 t in yours 22 to 9 in the other one), and the white reduction gear (16 to 10 in yours, 26 to 10 in the other one). Does this mean that it takes ~128.256 steps per rotation??

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Sridhar

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adafruit_support_bill
 
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Re: 28BYJ-48 12VDC stepper motor number of steps seems to be incorrect

Post by adafruit_support_bill »

I've done some more experiments with it. Although there are 8 poles in the stator, the rotor seems to have more. It doesn't operate consistently with the cover off due to alignment problems, but the best I can tell, the motor core has 32 steps/rotation. That gives 513.024 steps after the gear reduction, which is more consistent with your original estimate of 528 steps. I'll have the product description updated to 32 steps and a 16.032:1 gear ratio.

These motors were originally designed for automotive vent controls. Since these only move through a partial rotation, the odd gear ratios are not a big deal. It is strange that there is so much variation between different manufacturers of the same part-number. :?

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