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Topic: Stepper Motor is getting real warm... (Read 4827 times) previous topic - next topic


i am using a stepper motor Mitsumi M42SP-6NK

and a L298N Dual Motor Controller Module  with my arduino mega ...

any idea why is getting worm?

Code: [Select]

 Stepper Motor Control - one revolution
 This program drives a unipolar or bipolar stepper motor.
 The motor is attached to digital pins 8 - 11 of the Arduino.
 The motor should revolve one revolution in one direction, then
 one revolution in the other direction. 
 Created 11 Mar. 2007
 Modified 30 Nov. 2009
 by Tom Igoe

#include <Stepper.h>

const int stepsPerRevolution = 200;  // change this to fit the number of steps per revolution
                                     // for your motor

// initialize the stepper library on pins 8 through 11:
Stepper myStepper(stepsPerRevolution, 8,9,10,11);           

void setup() {
  // set the speed at 60 rpm:
  // initialize the serial port:

void loop() {
  // step one revolution  in one direction:
   // step one revolution in the other direction:


Apr 28, 2015, 09:06 pm Last Edit: Apr 28, 2015, 09:08 pm by jremington
any idea why is getting worm?
Assuming you mean "warm", heat is generated by current flowing through the windings. This is normal and unavoidable. Some motors are rated to operate normally at 80 degrees C or more -- check yours.


i guess so , datasheet dosent say much
i scavenge the motor from an old printer


What is the winding resistance, where is the datasheet and what supply voltage are you
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


If it's scavenged from a printer then it's only too hot when the smoke is released.  Warm is OK.
"The problem is in the code you didn't post."


the rated current is stated in the data sheet you linked to - are you sticking to it?


In general steppers are rated for 60 or 80C temperature rise above ambient, which is
a lot.  Most steppers are rated for heatsinking - ie being bolted to a metal frame that
helps take away the heat (since this is normal for motors).  If temperature is an
issue de-rate the current a bit.  Remember dissipation is proportional to current squared
so even a small reduction in current will make a difference.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


this the datasheet
Rated Voltage DC 12V DC 24V
Working Voltage DC 10.8~13.2V DC 21.6~26.4V
Rated Current/Phase 400mA(PEAK)
No. of Phase 2 Phase
Coil DC Resistance 5Ω/phase±7%
Step Angle 7.5°/step
Excitation Method 2-2 Phase excitation (Bipolar driving)
Insulation Class Class E insulation
Holding Torque 39.2mN·m 39.2mN·m
Pull-out Torque 23.2mN·m/800pps 17.4mN·m/2,000pps
Pull-in Torque 27.1mN·m/200pps 26.2mN·m/200pps
Max. Pull-out Pulse Rate 2,000pps 3,900pps
Max. Pull-in Pulse Rate 700pps 700pps

I forgot it and it worked for 20 minutes. the damn thing melt my mouse pad....
the resistance in windings was fine though.....

The power source that i feed it was 12v 1.5Amp  , so i think was over kill the data sheet say Rated Current/Phase 400mA(PEAK)  , so i have to use small amount of current


Apr 29, 2015, 04:48 pm Last Edit: Apr 29, 2015, 04:51 pm by jremington
You are not allowed to exceed ANY rating. 12 volts into 5 ohms is 2.4 amps, which is far higher than the 400 mA current rating.

For stepper motors, the voltage rating is usually irrelevant. It is the current rating that you must not exceed (steady state current).

That particular motor is intended for use with a chopper-type motor driver, like the Pololu A4988 breakout.


Apr 30, 2015, 11:21 am Last Edit: Apr 30, 2015, 11:26 am by gc9n

this is the motor ,


Are you saying that the  L298N Dual Motor Controller Module   that i use is incompatible with this motor?



Apr 30, 2015, 04:54 pm Last Edit: Apr 30, 2015, 04:56 pm by jremington
Are you saying that the  L298N Dual Motor Controller Module   that i use is incompatible with this motor?
Correct. That is a low impedance motor and is intended for a chopper driver.

The L298N motor controller will work if you use a high-wattage resistor in series with each motor winding to limit the current (say, 27 ohms, 10 watts, with 12V motor power supply), but that will waste a lot of power.


Apr 30, 2015, 07:54 pm Last Edit: Apr 30, 2015, 07:55 pm by MarkT
5 ohm is borderline low impedance, and it looks fairly small (rated current 0.4A suggests under 2W dissipation.

A4988 will run that sweetly from 12 or 24V.

But with 7.5 degree steps you may not need high speed.  L298 from 5V supply
might work (drops 2.5V or so, so about 0.5A to the windings) for low speeds
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


Perhaps you could add a resistor between the driver and the motor to reduce the current.

Sure the stepper motor will not step as strong... but it may still fit your project without having to go and get a chopper driver.

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