H bridge l298n in Parallel Burning Out After Some Time

[rodolfoviolac]

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?

[rodolfoviolac]

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?

[UKHeliBob]

Topic locked - duplicate post

Do not cross post requests for help as it wastes people's time and can be confusing

[TomGeorge]

Hi,
Welcome to the forum.
The l289 is a dinosaur of an H-Bridge.

The device uses BTJ rather than the more efficient MOSFET driver transistors.
OPs diag.

Do you have a heatsink on the IC?
If you look at the suggested circuits, they have a resistor Rs conected to pins 1 and 15, these are a current sense resistor to help regulated the IC.
What is the STALL current of your motor?
Can you post link to spec/data of the motor please.

But I suggest you go looking for a more efficient MOSFET type motor driver.
This site is a good place to start;

Pololu Robotics and Electronics

Tom....

[Ballscrewbob]

@rodolfoviolac

TOPIC MERGED.

You may want to READ THIS for future reference.
It will help you get the best out of the forum.

Bob.

[rodolfoviolac]

TomGeorge
Yes I have a pretty good heatsink on the IC.

Can you help me dimensionate this Resistor?
I'm not sure what is the stall current but 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.

Spec for the motor:

quanser

[TomGeorge]

Hi,
This is what I got from the Maxon site.
The nominal voltage is 24V, running the motor at 27V which I assume is the Absolute Max, will shorten its working life.
The stall current which is the max current it will draw, for example at startup can be as high as 10.4Amps.
Have you a DMM to measure the currents and voltages around your project?
I suggest you measure your motor current and the voltdrop across the H-Bridge.

Tom...

[MarkT]

10A stall current is far too much for any darlington-based motor driver, you need a suitable MOSFET H-bridge, checkout the wide range at polulo.com

[rodolfoviolac]

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). One on SENSE_A and the other one on SENSE_B.

• I Changed the heat sink that I 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!