H bridge l298n in Parallel Burning Out After Some Time

rodolfo's picture

Offline

Joined: Dec 03, 2019

Replies: 1
H bridge l298n in Parallel Burning Out After Some Time
December 3, 2019 - 9:21pm

Hi Guys,

I have a college project where I need to controll a motor (27V / 3 A), I used a H Bridge l298n in parallel to support the current, It worked for while and then stop but I don't know what was wrong. Does any body know anthing that could help me?

The motor is a Maxon 118752 precision brush motor (20 Watts) operating at 27 V max. The motor offers a peak current of 3 A, with a maximum continuous current of 1.2 A.

Specs for the motor:
made-for-science.com/de/quanser/?df=made-for-science-quanser-2-dof-serial-flexible-joint-usermanual.pdf

My circuit design:

Screen Shot 2019-12-03 at 8.34.41 AM.png

John_Kripto's picture

Offline

Joined: Aug 11, 2018

Replies: 36
You cant use L293D for your motors
December 5, 2019 - 11:25am

Look at the specification of L293D IC. 

https://components101.com/l293d-pinout-features-datasheet

It can only support a maximum continous current of 600mA and a peak current of 1.2A. But your motors here have a continous current of 1.2A and peak current of 3A which is simply too much for your L293D IC to handel. So there is no suprise that your IC is burning. 

You should upgrade to the L298 Motor driver IC (also available as module), which can handle current upto 3A for your application 

https://components101.com/ics/l298-pin-configuration-features-datasheet

Sourav Gupta's picture

Offline

Joined: Feb 12, 2018

Replies: 206
Use L298
December 5, 2019 - 12:05pm

L298 is the perfect choice. Change the driver

Debasis Parida's picture

Offline

Joined: Aug 22, 2019

Replies: 120
L298 H-bridge issues
December 5, 2019 - 12:53pm

Hi Rodolfo, as per L298n datasheet, it can withstand upto 2 AMP current for a single drive, but in your case it exceeds, as your peak current is 3 AMPs, it seems that, this is reason for which your driver can't drive the motor.For cross checking the issue you can just replace the motor with a lower current rating DC motor and recheck and check if the problem persists!!! Hope it helps

John_Kripto's picture

Offline

Joined: Aug 11, 2018

Replies: 36
L298 for 1.2A motor should work
December 6, 2019 - 10:47am

Hey Parida, the OP has said that his motor is rated with a continuous current of 1.2A and peak current of 3A which can be handled by L298 IC. According to the IC datasheet 

L298 current rating.PNG

The IC can deliver continuous current of 2A which should be enough to drive a 1.2A motor 

rodolfo's picture

Offline

Joined: Dec 03, 2019

Replies: 1
Fully Worked
December 13, 2019 - 7:15am

Hi guys,

Thanks for the support, I made some changes and fully worked, I did a lot of tests and it worked perfectly.

Changes that I made:

- I Changed the diodes to Schottky switching diodes (1N5819 1A 40V).

- I Added two Rs Resistors (0.56 ohm 1W) on SENSE_A and SENSE_B.

- I Changed the heat sink that a had to a large one.

The Rs resistors is very importante step, because they will help divide the current more equally to the both bridge that are in parallel, just to make sure that one bridge is not receiving more current that can really handle. I think all the changes above made the project work.

I'm very thankful for you all support!

Violet's picture

Offline

Joined: Aug 16, 2018

Replies: 41
Interesting!! How did you make current even on L293D
December 13, 2019 - 11:20am

Hi Rodolfo, Can you tell me how you use used the resistors Rs with Sense A and Sense B? I am also facing a similar problem, both my motors are not rotating in the same speed I think it is because they are getting different current values.

I would be great if you can show me a circuit diagram on how you done it.

Thanks!