motor shield r3 gets really hot with 12V dc motor

Hi,

I’m also new to the Arduino community.
So please explain things newbie way :confused:

I have:
1: Arduino uno r3
2: motor shield r3
3: a AC to DC adaptor with these specs:

  • Ingangsvoltage: 100 – 230 V AC/50 Hz
  • Uitgangsvoltage: 3/4.5/6/7.5/9/12 V DC
  • Uitgangsstroom: Max. 2250 mA
  • Max. vermogen: 27 W
  • Afmetingen: 88x51x42 mm
  • pluggen: 2.5 mm, 3.5 mm, 2.1 x 5.0 mm, 2.5 x 5.5 mm, 1.35 x3.5 mm, 1.7 x 4.0 mm, 0.75 x 2.35 mm
    4: a 12V DC motor. Of this i don’t have the exact specs. but i think is this:
    motor 12 v dc

5: The Code; its basic, just to get me started.

void setup() {

//Setup Channel A
pinMode(12, OUTPUT); //Initiates Motor Channel A pin
pinMode(9, OUTPUT); //Initiates Brake Channel A pin

}

void loop(){

//forward @ full speed
digitalWrite(12, HIGH); //Establishes forward direction of Channel A
digitalWrite(9, LOW); //Disengage the Brake for Channel A
analogWrite(3, 255); //Spins the motor on Channel A at full speed

delay(3000);

digitalWrite(9, HIGH); //Eengage the Brake for Channel A

delay(1000);

//backward @ half speed
digitalWrite(12, LOW); //Establishes backward direction of Channel A
digitalWrite(9, LOW); //Disengage the Brake for Channel A
analogWrite(3, 123); //Spins the motor on Channel A at half speed

delay(3000);

digitalWrite(9, HIGH); //Eengage the Brake for Channel A

delay(1000);

}

Now the problem is that the motor shield (center big chip) gets really hot and i have to turn it of. It begins to smell.

I have done reading a lot on this forum and i think that the motor draws to much amps (current)
is this correct? or? Is there a way to avoid this overheating problem with this shield?

Even if i set the adaptor to output 9V it still gets very hot.

Hope some can help.

tnx

That motor might be trying to draw 30A or more. The motor shield can only deliver 2A. That is not a good combination.

The current a motor needs will depend how much load it is under. So what is your motor actually driving?

Steve

That motor shield uses an ancient bjt based L298 motor driver chip with a typical drop of 2.5volt@1Amp. That means a dissipation of 2.5watt with a 1Amp motor.

Your motor seems to draw 1.2Amp unloaded, and has a load and stall current much higher than that.

Glue a heatsink to the chip, and plug and pray. Or get a better (mosfet based) motor driver. Pololu.com has a good selection. Leo..

I want to make a actuator my self. The motor should drive this:https://reprapworld.de/products/linear_motion/tr8x2_leadscrew_8mm_30cm/

Another issue i just came across is that if i hold the motor shaft with 2 fingers and apply a smal smal minimum amount of pressure the motor wont turn at all. it just zooms. So i do believe that the motor need much much more amps to be able to start with sufficiënt torque.

am i correct?

It seems you try to use a high RPM brushed motor for a lead screw that needs a low RPM stepper motor. No practical experience there (I have a factory made CNC machine). Leo..

That's true. I'm trying to figure things out and want to make my own Actuator.

I have ordered this motor: NEMA17

If i'm correct this one should do the trick? And i can connect him to the arduino motor shield r3? right?

No, that needs a stepper driver like a DRV8825

ok, i have also this driver here with me.

TEPPER_MOTOR_CONTROLLER_MODULE.pdf

can i use this one? or should i just order a beter driver?

tnx for the help! i appreciate it!!

Same L298 chip, different package (flat vs. upright)

That breakout board migh run a bit cooler because of the heatsink.

Those chips are really meant for higher voltage, low current motors (e.g. 24volt <1Amp).
The reason you find them in the Arduino market, along with the smaller L293, is because they are cheap.
Technology has advanced a lot since they have been designed (35+ years ago).
Leo…

can i use this one?

No.

or should i just order a beter driver?

Yes, see reply #6. Pololu.com sells DRV8825 drivers. Be sure to follow directions and set the current limit to 1.5A or less.

Ok tnx. It did work! But this L298 driver gets pretty hot i notist. I had it run a NEMA 23 1 Nm driver back and fort voor about 1 hour. With 12V 2.2A adaptor.

Therefor just order 4 of those DRV8825 drivers. :D I need to run 2 or 3 Nema stepper motors.

I will wait for the package to come. And read the instuctions.

Be sure to follow directions and set the current limit to 1.5A or less.

Because i don'f fully understand the above sentense. :confused:

Kumalix: ok, i have also this driver here with me.

TEPPER_MOTOR_CONTROLLER_MODULE.pdf

can i use this one? or should i just order a beter driver?

tnx for the help! i appreciate it!!

No, I said you need a stepper driver, not a motor driver, because you always need a current-controlling stepper driver for low-impedance bipolar stepper motors (these motors are current driven, not voltage driven).

Ok, i got the dvr8825.. it's really small :o

Now the question is how much voltage and current do i have to have?

Like i first posted i got this AC to DC adaptor: - Voltage can be set to: 3/4.5/6/7.5/9/12 V DC - Current: Max. 2250 mA - Max. 27 W

and: This motor It sais 1.7A.. does that meen for each coil? or for both?

also where do i set the current with the dvr8825? in arduino IDE?

thanks for helping!

Google setting the current for the DRV8825, there are resources out there, certainly at pololu.com for one. The 1.7A is the current you need to set the driver too, there is only one setting. If you are interested in the details read up about microstepping stepper drivers, for instance the datasheets for chips like the DRV8825, A4988

Ok tnx. I have been reading last night for about 8 hours :sweat_smile:

I have set the correct current (VREF) with the potantiometer on the dvr8825 to 0.8 Volts. with the formula: Current Limit = VREF × 2 So that should give 1.6 Amps to each coil?

But now i have the feeling that the torque of the Nema17 motor not that strong is. I can hold the shaft of the motor with 2 fingers and the motor slips. (i can stop the shaft from spinning with 2 fingers).

Normaly i would say that the motor isn't strong enough. But with de L298 chip i had much more torque and could not stop the shaft with 2 fingers. The motor did get a little hot??? While with dvr8825 it stays cool.

Is there a reason for this?

Yes you were overdriving the motor and the L298, causing them to both fail. Driving a stepper at its rated current is a thermal limit - any higher and the motor risks cooking and either burning its windings or demagnetizing its rotor due to the Curie limit.

I thought so, tnx for the confirmation.
Currently im using the NEMA 17 motor to test my Actuator with accelstepper.h.
And it’s looking good but…

When i set the stepper mode to or the motor virates a lot on acceleration/deceleration speeds (low speeds). It’s just to loud.
When i set the mode to <1/4 step> the motor runs fine but i don’t have enough speed.

So need it to run on or but without the acceleration/deceleration vibes.
What can i do about this?

  • Something in the code?
  • Bigger motor (NEMA 23)?
  • Or could it be my wiring?

Tnx for the help.
The driver is dvr8825.