# Question about a 24V geared motor and Voltage regulator

#### Lerior

Joined Jan 18, 2018
28
Hello,

I'm using a voltage regulator (DC-DC) that will take 5V input from my arduino and step it up to 24V straight to power a DC motor. The motor specs are: 24V, 250W, 3300RPM (No load), and 0.8 Nm torque. It is classified as a geared motor. From my understanding, the motor needs about 10.4A (P=IV) to run at its full potential. However, the voltage regulator that I purchased has a maximum of 10A output that will be send to the motor to run it. So my question is, will that affect the voltage regulator (Increase its power dissipation?) and burn it, or is it going to be sufficient enough for the motor to work? Thank you.

Joined Jul 18, 2013
25,467
That will most likely be under rated, you also have to allow for the estimated load.
Max.

#### Lerior

Joined Jan 18, 2018
28
That will most likely be under rated, you also have to allow for the estimated load.
Max.
Would you mid elaborating more?

#### Ylli

Joined Nov 13, 2015
1,058
will take 5V input from my arduino and step it up to 24V , the motor needs about 10.4A
So your arduino can supply over 60 amps?

10.4 * 24/5 * 1/0.8 = 62.4 amps

#### Lerior

Joined Jan 18, 2018
28
So your arduino can supply over 60 amps?

10.4 * 24/5 * 1/0.8 = 62.4 amps
This is a group project and one of our team members is responsible for arduino. This is my first time trying to learn about arduinos, what is your suggestion to prevent that? Initial plan is:

The programmed arduino is going to control membrane switches (to control the direction of the motor), and send a voltage signal (5V) to voltage/power regulator up to 24V.

#### KeepItSimpleStupid

Joined Mar 4, 2014
5,088
I'm using a voltage regulator (DC-DC) that will take 5V input from my arduino and step it up to 24V straight to power a DC motor. The motor specs are: 24V, 250W, 3300RPM (No load), and 0.8 Nm torque. It is classified as a geared motor.
You probably should go the other way around. The system supply being the larger power/voltage and the Arduino power derived from the higher power and voltage,

The motor torque is proportional to I and the motor RPM is loosely proportional to V = Vm-I*Im where Vm is the voltage across the motor which is largely an unknown. When I is zero the motor acts as a tachometer.

The motor has inductance, BUT the supply has to be able to deliver the locked rotor ) amps for a short time.

Old 8-track decks used to use the V-Im*R method to control RPM.

If the motor is a DC permanent magnet type of motor then PWM is usually used. This keeps the torque near the max for the motor at nearly all RPM's.

Better and more complex control would be obtained by a BLDC motor. e.g. brushless 3-phase. That's more complex to control.

Power dissipation is primarily the voltage dropped across the component(s) * the current. PWM increases the efficiency becase the controlling devices are either full on or full off.