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[DPRG] interesting TI SN754410 failure mode

Subject: [DPRG] interesting TI SN754410 failure mode
From: Dave Peterson robodave1 at comcast.net
Date: Mon Apr 24 03:57:51 CDT 2006

I've actually done this in testing out an NMIH-0010, in
trying to get it to fail. Essentially what is needed is to
stall a motor that requires more Amps than the device is
designed for, using a power source that can actually dump
the current into it. In the test, I'd stalled a pair of
Faulhaber 2842-012C motors which are rated at a stall
current (not free run) of 2.2 A on a 12 volt source. The
power source was a pair of 7.2 volt NiCad racing packs
connected in series and freshly charged, probably ranging
between 14.4 and 15 volts. It is likely that 2.6 to 2.7 A
was trying to go through each side of the bridge before it
had a pretty cool looking flame failure. It had to be driven
to do that though, there was no "kind of turned off" or on
about it. All I had to do afterward was plug in another
chip, but these guys look like they torched the socket too.
Might be good to check the wiring a bit. My thoughts at the
time were on how to force a stall on this in a DPRG contest
to go for the "My Robot Fried " award. . Lesson from this
test : use an h-bridge capable of carrying more current than
your motors stall at, and check to see if there is some sort
of short across your motor outputs (and check for heat
dissipation as well, more likely long term limiting factor
and faiilure mode).


----- Original Message ----- 
From: "R. Steven Rainwater" <srainwater at ncc.com>
To: "DPRG" <dprglist at dprg.org>
Sent: Sunday, April 23, 2006 12:49 PM
Subject: [DPRG] interesting TI SN754410 failure mode

> I ran across this blog entry today and thought some other
DPRG folks
> would get a kick out this TI h-bridge chip's
flame-emitting failure
> mode.
> -Steve
> _______________________________________________
> DPRGlist mailing list
> DPRGlist at dprg.org
> http://list.dprg.org/mailman/listinfo/dprglist

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