Will this still work with a more powerful motor?

Thread Starter

byrlle09

Joined Mar 2, 2017
7
So I have this project(RC Multipurpose planter with solar panel) for my final year in mechanical engineering, and i have been researching on electronic schematic diagrams. I don't have much knowledge on making circuit diagrams so i searched for one.


And this is what i have found, a simple and small diy remote controlled robot schematic diagrams. (See site and pics)

(Credits to the publisher)

https://diyhacking.com/remote-control-car/


Transmitter Circuit:


Receiver Circuit:


It is relatively simple and easy to build. I think this is gonna work for my project.

However...
I'm gonna need a larger dc motor since the weight of my robot is about 30kg (about two 40W power of a 12VDC motor)(Moving at 2km/hr)
And im gonna add a solar panel for recharge-ability and sustain.

My questions are:
1. Will this still work and not fry up even if i use a larger motor? (Since ill have a larger motor, ill have a higher amperage for a constant 12V DC motor)
2. How do i configure this circuit to meet my required power to drive my 30kg robot.
3. How and where do i install my solar panel?
4. Any recommendations?
5. Im new, please don't judge (Not a question XD)
 

Thread Starter

byrlle09

Joined Mar 2, 2017
7
Oh yes. Im gonna use geared motor to increase torque. My concerns are my circuits gonna work fine? I don't want heat or fires in my circuits. And see my other questions.
 

bertus

Joined Apr 5, 2008
21,452
Hello,

The given L293 will work upto 1 A, so 12 Watts @ 12 Volts.

L293_feature.png

If you want to use larger motors, you must choose an other driver.

Bertus
 

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Kjeldgaard

Joined Apr 7, 2016
451
A little thoughts about the project.

The first task is to find another motor control circuit. L293D is a maximum of 0.6 amps per motor.

Immediately, I believe that it is something with an IC with four external MOS transistors per motor. These driver ICs should also have an over current limitation.

Additionally, I am a bit worried about starting two 40 Wats motors at full power, some ramping of the motor power, both at start and stop should also be considered.
 

MaxHeadRoom

Joined Jul 18, 2013
23,371
If you haven't built it yet, one aspect of Mechatronics is sizing and using the most efficient parts, and by increasing the size of the drive, which is most likely going to consume more current, it is definitely counter productive to using the highest gearing you can apply in order to lower the current demand, especially in a battery, mobile application.
Max.
 

shortbus

Joined Sep 30, 2009
8,719
The first task is to find another motor control circuit. L293D is a maximum of 0.6 amps per motor.

I see many projects using this outdated chip. Don't really understand why. Guess it's like the LM741 opamp, so outdated but will never go away. and the manufacturers won't stop making them on there own because they still sell and the tooling has paid for its self.

Many people don't know there is and has been a higher power substitute for it, the SN754410.
www.ti.com/lit/ds/symlink/sn754410.pdf
 

Thread Starter

byrlle09

Joined Mar 2, 2017
7
A little thoughts about the project.

The first task is to find another motor control circuit. L293D is a maximum of 0.6 amps per motor.

Immediately, I believe that it is something with an IC with four external MOS transistors per motor. These driver ICs should also have an over current limitation.

Additionally, I am a bit worried about starting two 40 Wats motors at full power, some ramping of the motor power, both at start and stop should also be considered.
Ill try to find another motor driver to replace to the circuit

What about starting 2 motors? Are you concerned about the battery? the circuit? Or the motor? would you care to explain?
 

Thread Starter

byrlle09

Joined Mar 2, 2017
7
If you haven't built it yet, one aspect of Mechatronics is sizing and using the most efficient parts, and by increasing the size of the drive, which is most likely going to consume more current, it is definitely counter productive to using the highest gearing you can apply in order to lower the current demand, especially in a battery, mobile application.
Max.
I'm at the designing phase. It seems like im gonna need a higher current for a higher power output.
 

Thread Starter

byrlle09

Joined Mar 2, 2017
7
I see many projects using this outdated chip. Don't really understand why. Guess it's like the LM741 opamp, so outdated but will never go away. and the manufacturers won't stop making them on there own because they still sell and the tooling has paid for its self.

Many people don't know there is and has been a higher power substitute for it, the SN754410.
www.ti.com/lit/ds/symlink/sn754410.pdf
Im a newbee. And i haven't known any of these. Maybe these are entry chips. Like how you learn to ride a bicycle before you could drive a motorcycle.

Anyways, If i change my motor to 36V, is this feasible? im gonna lower power to 36W(And so lose speed) But is it feasible?
 

djsfantasi

Joined Apr 11, 2010
7,763
Can i use this motor driver(MC33926)? How do i replace this from l293d?

https://www.pololu.com/file/download/MC33926.pdf?file_id=0J233
Earlier you stated two factors influencing you design. Your motors are 12VDC motors. And secondly, they draw 40W and I am assuming each.

That means according to the definition of Watts, that each motor is going to draw 3.3A. Times two is 6.6A. The recommended maximum current draw of the 33926 is 5A. You are over. Even if you weren't, it is too close to the max. You need some headroom.

Of course, if you are using two drivers, you'll be ok if it is heat sinked properly.

Do you know the stall current of the motors? That is what you need to size your driver for. It may be more than the calculated value given the stated Watts.
 
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