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[SOLVED] Stepper motor is not running smoothly?

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Member level 1
Feb 14, 2012
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Hi Everyone,
I am driving stepper motor with L297 & L298, it runs but its rotation is not smooth, the motor viberates and produces sound like buzz. anyone please help me how can i remove or minimize its viberation? I will wait for your response.

Thanks in advance.


You need to show your hardware diagram, software code and motor details.

I have implemented the sample circuit in the l297 data sheet at page first, here is a link

I am just applying clock from external, remaining configuration pins are connected to ground or 5V accordingly. i have also connected capacitors on 36V and 5V supply. Control, home and sync pins on L297 are not connected.

Here is motor specifications
Bipolar stepper motor

Amp/ Phase 6.30
Holding Torque (oz-in) 1288.0
Holding Torque (N-m) 9.10
Resistance (Ohm/Phase) 0.5
Inductance (mH/Phase) 4.1
Inertia (oz-in^2) 21.90
Number of Leads 4

I will wait for your reply.

Your poor L298 is goin' to blow sky high. Check it's datasheet on max current.
Next, the Step pulse stream should be jitter free, you should ramp your step frequency because if you start with the high step frequency your stepper may not start to spin due to it's rotors high rotational mass.
Thanks ZASto,
the max current of L298 is 4A, but i am trying to run it with minor load on motor, for this it takes upto 2.5A, which is in the range of L298. and the frequency i am applying on pin18 is pure square wave.

A steper motor driven conventionally will not have a smooth rotation due to its working principles. If you want to drive a stepper smoothly use microstepping technique. In addittion check that you are ramping speed gradually as a too high speed will make the stepper vibrate and not turn properly.

According to datasheet, you will have to calculate the current limiting resistors so that the current DOES NOT exceed the safe ratings of L298. You will have to put them on the substantial heatsink.
As of Max current, 4A is on the chip basis not per channel. Max repetitive current per channel (80% ON / 20% OFF) is 2.5A
Your motors can draw as much as 6.3A per phase, so, to be on safe side for your L298 0.5 Ohm resistors are needed, as stated in the L297 datasheet.

Also you have to ramp-up your pulse frequencu (ramp-up = gradually increase), as the stepper motor can not start istantly at the desired speed due to it's rotor's moment of inertia.
For "smoother ride" use the Half Step feature of L297

On the other side, microstepping is simulating Sin/Cos waveforms of the current through the motor phases, but it is not adding to the position accuracy.

My recomendation for your "beasts" are Gecko G203V drives (
Thanking you all, the problem solved.

- - - Updated - - -

Thanking you all, the problem solved.

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