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 Robotics / Handy Board / 2948
2947  |  2949
Subject: 
Burning hot motor driver chips.
Newsgroups: 
lugnet.robotics.handyboard
Date: 
Sun, 9 Nov 1997 03:55:34 GMT
Original-From: 
Anthony Oren Loeppert <(oren@mail.)spamless(utexas.edu)>
Viewed: 
1612 times
  
After not doing anything with my HB for a few months, I decided to buy a
cheap RC car and use it as a platform.  Anyway, I get a car that takes 6 AA
batteries because I figure that the main motor is probably 9v (maybe that
was a faulty assumption).  So I connect the steering motor to motor1 and
the drive motor in motor3, so each motor has it's own driver chip.  Well
after a few cycles of the below code, the drive motor ceases to get enough
power to move the car (the motor begins to spin if I pick the car up).
Upon burning my finger, I discovered that the chip running the was
extremely hot.  So my question is: Is this motor simply drawing too much
current?  I thought the L293D (which is what I am using) had some sort of
built it cut off if things got intolorable for it.  I also understand that
the L293D can be piggy backed, but will that give me enough amperage to run
a typical RC car motor?  Am I going to have to use an alternate driver?

Thanks for any suggestions/explainations,

//test drive
int main()
{
int i;
i=0;
while(i<1000)
{
fd(3);msleep(1000L);
off(3);msleep(250L); //attempt to give chip a break
if(digital(8))
{
bk(3);msleep(500L);
fd(1);msleep(1000L);
off(1);
}
i++;
}
return 0;
}

Anthony Oren Loeppert                   ***
http://www.cs.utexas.edu/users/oren/   *  o*
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Message has 3 Replies:
  Re: Burning hot motor driver chips.
 
Anthony, (...) Yes it sounds like it. (...) It does. The L293D still works after it cools off, doesn't it? (...) I suspect you are going to need more than just two piggy backed L293D. (...) You might have a look at Ben Wirz website, he sells various (...) (27 years ago, 9-Nov-97, to lugnet.robotics.handyboard)
  Re: Burning hot motor driver chips.
 
Hello, RC car motors pull a lot of current, from 2A to 8A. The L293D chip goes up to 1A peak (for some miliseconds) before it shuts down. I suggest bypassing the L293D chips and using something like the LMD18200. (URL) Good luck, Marco A.A. de (...) (27 years ago, 10-Nov-97, to lugnet.robotics.handyboard)
  Re: Burning hot motor driver chips.
 
Anthony, As you've no doubt heard, RC motors take much more current than the Handyboard can supply. To control RC motors your only choice is to create a separate H-bridge to drive the motors. You can do this fairly inexpensively with power (...) (27 years ago, 10-Nov-97, to lugnet.robotics.handyboard)

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