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Topic: Stepper Motor not spinning (sometimes) (Read 676 times) previous topic - next topic

TheAthenian

Hi everyone,

I'm working on a project which requires me to use steppers driven at specific frequencies and for specific time intervals. The frequency which I'm driving the driver (A4988) is approximately 2093Hz and i'm only driving it for intervals of about 0.4s. So basically, I drive the steppers for 0.4s at the aforementioned frequency. This process is then repeated many times. What I've noticed is that the motor vibrates but does not spin. Is the timing to short for the motor to overcome inertia? When I change the duration of the pulse to ~0.6s it starts spinning. What could be the cause of this?

EDIT: The steppers are from ebay so theres no datasheet, they are NEMA17 and have 'KS42STH34-1504A' written on the side of them.

Grumpy_Mike

Sounds like you are stepping them too fast for the current you put through them.
How are you driving them?
What current have you set your driver to?
What voltage are you using to drive them?
What is the resistance of the coils when measured with a DVM?

MarkT

You have to ramp the step-rate up and down if you want the motor to keep  up
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

TheAthenian

@Grumpy_mike I'm not in the lab so I can't measure current/voltage. From what you're saying a high current requires longer step time? Why is that?

Thanks

Grumpy_Mike

Because of the time it takes for current to reach its maximum in an inductor.

Why can't you answer my other three questions?

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