Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: dual on December 03, 2009, 01:10:01 PM

Title: Preventing Current stall
Post by: dual on December 03, 2009, 01:10:01 PM
I'm using the Tamiya 980112M Mabuchi FA-130 Motor (Specs: runs at 3V, stall current: 2.10 A, stall torque: 36 g-cm) and SN754410 Hbridge with 1A continuous current. The problem is I get too much stall that it heats up my Hbridge pretty fast causing the current output to decrease and slow down the speed of the motors totally. Unfortunately for me, it's too late to get replacement parts. So I was thinking about just compensating by preventing the current stall in software. Let me know if they're bad ideas. Thanks.

Here are my ideas:
1.) I used to always reverse my direction very quickly and that causes current stall. So instead of reversing the direction, I will make use of differential drive and smoothly decrease the voltage of one wheel to make a rotation or turn.

2.) Get a heatsink for my HBridge to suck up the heat.

3.) Make sure to run the robot in as much smooth surface as possible to prevent torque stalling.
Title: Re: Preventing Current stall
Post by: chelmi on December 03, 2009, 02:17:05 PM
The stall current is way over the limit of the component. Adding a heatsink could help but there is no guaranties the motor driver wont burn.

A solution is to stack two SN754410.

I used the same motors and had similar issues. My solution: get new motors. I know you have a time constraint, but Pololu shipping is pretty fast if you are in North America.
I bought the following motors: http://www.pololu.com/catalog/product/1117. (http://www.pololu.com/catalog/product/1117.)