Author Topic: Stepper motor excessive current draw only on first idle  (Read 810 times)

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Offline newtekuserTopic starter

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Stepper motor excessive current draw only on first idle
« on: April 01, 2023, 05:03:20 pm »
My 5V stepper motor draws 650mA (driven by ULN darlington array) but only on first idle. I understand the draw is higher when idle, but in my case the draw drops to ~330mA after rotation and going back to idle.
For some reason it only does that the first time after I power on the circuit. Any ideas as to why it's doing this?
 

Online langwadt

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Re: Stepper motor excessive current draw only on first idle
« Reply #1 on: April 01, 2023, 05:25:43 pm »
how are you driving it?

two coils on vs. one coil on?
 

Offline newtekuserTopic starter

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Re: Stepper motor excessive current draw only on first idle
« Reply #2 on: April 01, 2023, 05:54:44 pm »
One coil energized at a time.
 

Offline PeterG

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Re: Stepper motor excessive current draw only on first idle
« Reply #3 on: April 02, 2023, 01:04:19 am »
Double check the state of the output  pins on power up. Looks like your energizing both coils on power up.
Testing one two three...
 
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Offline newtekuserTopic starter

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Re: Stepper motor excessive current draw only on first idle
« Reply #4 on: April 02, 2023, 05:47:16 am »
Double check the state of the output  pins on power up. Looks like your energizing both coils on power up.

Thank you, that's what it was! I also made sure to set the port bits to low after performing any rotations.
 


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