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[DPRG] motor driver overheating

Subject: [DPRG] motor driver overheating
From: Jim Brown james_121 at yahoo.com
Date: Sun Oct 15 21:44:01 CDT 2000

Well, you could always use 3906 & 3904 transistors
and make your own h-bridges.  Of course, you'll still
have problems with heat.  I can't imagine if you're
using a really small motor that you'd be having
so much trouble with heat.  Sometimes if you look
at the datasheet for the part it will call out 
additional components such as flyback diodes and
such.  You might want to check to see if there's
something like that.

--- Matt Middleton <ussf at pentagon.navy.org> wrote:
> 
>   Thanks very much for the help Jim.  Is it possible that
> the motors could
> be too small for the driver chip.  They originally came
> with a battery box
> to hold two AA batteries.  Unfortunately this voltage is
> not enough for the
> l293d.  With PWM, however, I think it is only getting
> like 3.5 volts per
> motor which i can further adjust down.  I don't know if
> this is making it
> over heat or not.  Do you happen to know of any smaller
> motor driver chips
> that will work with a 3V source?
> 
> 
> 
> -----Original Message-----
> From: dprglist-admin at dprg.org
> [mailto:dprglist-admin at dprg.org]On Behalf
> Of Jim Brown
> Sent: Sunday, October 15, 2000 7:34 AM
> To: Matt Middleton
> Cc: dprglist at dprg.org
> Subject: Re: [DPRG] motor driver overheating
> 
> 
> 
> It sounds like you answered your own question (that
> you probably need a heat sink).  However, here's some
> suggestions you can try:
> 
>   1.  Make sure your motors aren't under heavy load.
>       Motors under heavy load or stalled suck way
>       more power!  Try to avoid stall situations.
> 
>   2.  Switch to a different motor that doesn't use
>       so many ma.  Is your motor bigger than a quarter
>       in diameter?
> 
>   3.  Switch to a different h bridge chip like an
>       l298 or a 18200.  They handle more amps and
>       are easier to heatsink.
> 
>   4.  Use bigger traces if you make your own pcboard.
>       This will work like a heat sink sort of.
> 
>   5.  Switch to alkaline batteries.  Nicads can drop
>       huge amounts of power at once.  Alkalines can't
>       supply so much power.  If your robot stalls, it'll
>       possibly keep it from overheating.  This suggestion
>       probably won't help much, btw.
> 
>   7.  Get a heat sink.
> 
>   8.  Get a fan.
> 
>   9.  Get a peltier junction.  :-)
> 
>   [insert disclaimer here]
> 
> --- Matt Middleton <ussf at pentagon.navy.org> wrote:
> > I have a TI SN754410 motor driver, which is essentially
> > the same thing as
> > the l293d.  I am running two small mabuchi model motors
> > on a 4.8 V NiCd
> > Battery.  After 30s - 1 minute, the motors begin to
> lose
> > power, and I
> > believe that it is the controller switching into
> thermal
> > shutdown mode.
> > Other than getting a heatsink, I don't really know what
> > to do to prevent
> > this from happening, so any suggestions that someone
> > might have is welcome,
> > I would sure appreciate them.
> >
> > Thanks,
> >
> > Matt Middleton
> >
> >
> >
> > _______________________________________________
> > DPRGlist mailing list
> > DPRGlist at dprg.org
> > http://nimon.ncc.com/mailman/listinfo/dprglist
> >
> >
> 
> 
> =====
> ------------------------------------------------------
> Jim Brown      james_121 at yahoo.com
> 
> jimgbrown at home.com http://members.home.net/jimgbrown
> jim_brown at adc.com jbrown at dprg.org  http://www.dprg.org
> 
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> 
> 


=====
------------------------------------------------------
Jim Brown      james_121 at yahoo.com

jimgbrown at home.com http://members.home.net/jimgbrown
jim_brown at adc.com jbrown at dprg.org  http://www.dprg.org

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