Is this an appropriate shield+P/S+motor combo?

Goal: Run 24V motor and a 12V DC motor simultaneously and both in one direction.

Problem: I hooked up the 24V DC motor to my KOOBOOK L298P Shield R3 and my DC 9V 1A power supply and it just hummed, so I am assuming I do not have enough power supply to run the motor.

Questions:

  • Can I hook up a 24V 4A Power Supply to the KOOBOOK L298P Shield?
  • I see the shield has a max power of 25W but I intend to have these motors running slow and with a light load, but is there a more appropriate and cost effective shield?
  • Can I run a 24V and a 12V motor on the same shield?

All referenced Components: (Can only post two links as a new user but the component titles are the amazon listing titles)

Arduino Uno R3

[24V Motor](https://www.amazon.com/gp/product/B08D3SGFSL/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1)

[12V Motor](https://www.amazon.com/gp/product/B08BL9ZC3P/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&th=1)

L298P Shield I have: KOOBOOK 1Pcs L298P Shield R3 Motor Driver Module Expansion Board H-Bridge 2A For Arduino UNO 2560

Power Supply I have: ELEGOO AC 100V-240V Converter Adapter DC 9V 1A Power Supply US Plug 5.5mm x 2.5mm 1000mA Power Adapter Wall Charger Adapter Compatible with Arduino UNO MEGA with UL FCC CE Certificate

Power Supply I am considering: SHNITPWR 24V 4A Power Supply Adapter 100~240V AC to DC 24volt Converter 96W 24 Vdc 4 Amp 3.75A 3.5A 3.3A 3A Transformer 5.5x2.5mm Tip for 5050 3528 LED Strip Light 3D Printer CCTV Camera LCD Monitor

Code I used:
int E1 = 3;
int M1 = 12;
//int E2 =11;
//int M2 = 13;
void setup()
{
pinMode(M1, OUTPUT);
// pinMode(M2, OUTPUT);
}
void loop()
{
{ int value;
for(value = 150 ; value <= 255; value+=5)
{
digitalWrite(M1,HIGH);
// digitalWrite(M2, HIGH);
analogWrite(E1, value);
// analogWrite(E2, value);
delay(100);
}
delay(1000);}}

The L298 has one power input for the motors; you can supply either 12V or 24V in your situation.

Further it’s a little outside my area of expertise.
The max power dissipation for the L298 is 25W; so it can do 24V at 1A or 12V at 2A.

If you only need one direction, use a logic level MosFet that suites tour needs; make sure it’s a logic level one! In that case, don’t forget a flyback diode. See e.g. https://www.gammon.com.au/motors for a schematic and explanations.

It is hard to answer, I could not find the power requirements of the motors. Current is all important. I would suggest you get the current then find an alternate to the L298 bridge. If you want a simple solution, use logic level UIS rated MOSFETs, that saves you the external flyback diode. Use two MOSFETs, one for each motor and the wiring is simple. All power supply grounds connected together including the arduino. No current through the Arduino. Source of each MOSFET is ground, the Drain goes to the motor and the gate to the output pin of the Arduino assuming 5V logic. Add a 10K pull down resistor to each of the Arduino output pins to be sure the MOSFETS are off during reset etc until your software gets control.

1 Like

Thanks,

I bought these:

PSU: COOLM DC 12V 4A 48W Power Supply
MOSFET (Q1): IRL7833 IRL7833PBF N Channel 30V 150A Power MOSFET TO-220AB
Diode (D1): MCIGICM 15SQ045 Schottky,15amp Diode Axial Schottky
Motor: Link

I am going to wire it exactly like this: (https://www.gammon.com.au/images/MOSFET_low_side_driver.png)

Question:
Motor specs say, “Rated Current: 0.5A”
PSU claims 4A output

What will limit the current? Won’t the motor just receive 4 Amps every time the MOSFET is letting current sink/through the motor? If that’s is the case what is the simplest way to limit the current? OR Is the current just regulated by the PWM from the controller pin acting on the gate?

A motor draws what is needed. Compare the motor e.g. with your house. A light bulb (your motor) is rated e.g. 60W. So it draws 220/60 = ~ 250mA. But usually the distribution board (your power supply) is fused with e.g. 16A (so can ‘deliver’ 16A).

Note:
Motors draw a lot of current at startup; once they are running the current consumption is lower. You can measure the motor resistance and determine the max. current. E.g. if the coil resistance is 10 Ohm, the startup current will be 12/10 = 1.2A.

1 Like

Thanks for the replies/explanation sterretje and gilshultz. I am successfully running the motor with the components listed in my 2nd post and everything appears to be staying cool after running for an hour.

Overkill on the MOSFET but if given a choice I would do exactly what you did. It is much easier, sometimes even less expensive to use silicone and drive it properly then using heatsinks. You can use D1 but it is not needed, look at the UIS rating of the MOSFET. R1 should be less then 50 Ohm, R2 is great, it guarantees your reset condition etc. If you have access to a scope measure the rise and fall time of the gate and output with the 150 then the 50 ohm resistors.

Alas neither motor seems to have any datasheet so we don’t know the stall currents
for either - they look large enough to maybe be beyond a L293D or L298 shield though.
So if they are struggling perhaps upgrade to some MOSFET drivers such as from the
range at pololu.com.

I have designed a small pulse width modulation DC motor driver circuit based around a MOSFET that will meet your requirements here. You would need one circuit per motor as you have one 24V motor and one that runs from a 12V supply. The circuit configuration is similar to the one you are using but has a few extra components added to give EMI filtering, which can affect the operation of your micro-controller.

I have written up the project at PWM DC Motor Driver - I give more information on the design of the circuit as well as a guide to building the circuit on both stripboard and a printed circuit board.

Hope the information might be useful to you.

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