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MOTOR JITTERS AT 12 Volts
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MOTOR JITTERS AT 12 Volts

by MarkRCP on Thu Nov 12, 2020 1:29 am

Hello,

I am using an Arduino UNO, motor shield (#1438) and NEMA 17 stepper (#324).
Running the basic stepper motor test script from Adafruit.
The power jumper is off, running Arduino with USB and stepper with adjustable supply (10 amp max).

If I set the motor voltage to 5 volts the motor runs smoothly and completes all the routines (single, double, interleave and microstep)

If I set the motor voltage to 12 volts the motor barely runs on SINGLE step and is very loud and jittery.
DOUBLE step is slightly better (but loud) and INTERLEAVE is the same. On MICROSTEP is runs ok (smoother), but louder than at 5 volts.
I am able to monitor the current, it never exceeds .340 amps.

What I am doing wrong?

Mark

MarkRCP
 
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Re: MOTOR JITTERS AT 12 Volts

by adafruit_support_bill on Thu Nov 12, 2020 7:13 am

Since stepper motors move in discrete steps, there is vibration due to the acceleration and deceleration that happens with each step. Powering with a higher voltage, the magnetic fields are stronger, and so are the resulting vibrations.

The magnitude of the vibrations will depend on the mass distribution and damping characteristics of the motor and mechanism it is attached to. A loose motor sitting on a desktop will vibrate quite a bit. And on some surfaces it will make quite a racket.

In practice, vibrations are typically tamed by some combination of damping (e.g. shock mounting the motor), and/or choosing step-rates that avoid resonant frequencies of the mechanism. Microstep or interleave step modes can help as well by reducing the acceleration forces.

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Re: MOTOR JITTERS AT 12 Volts

by MarkRCP on Sun Nov 15, 2020 7:55 pm

That makes sense. Thank you for the information. I just started using stepper motors and on the steep part of the learning curve.

Mark

MarkRCP
 
Posts: 2
Joined: Thu Nov 12, 2020 1:14 am

Please be positive and constructive with your questions and comments.