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[DPRG] thermal glue

Subject: [DPRG] thermal glue
From: David Peterson robodave1 at attbi.com
Date: Sat Dec 21 15:02:01 CST 2002

Hey Daryl,
   One thing to consider, is that at a 50 Hz rate you are pulsing your
motors at, may be a constant stall condition, upping the amount of current
trying to go through the motor and h-bridge. This wouldn't seem to be above
the electrical time constant of the motor, and maybe not even over its
mechanical time constant, so your motor may always be trying to go-coast,
go-coast from near low speed current draw, or forward-reverse,
forward-reverse at low speed if trying to drive in locked-antiphase mode..
If you are trying PWM to control speed, might try a significantly higher
frequency to smooth things out a bit. Have any specs about that 6 volt motor
you are trying to drive?

----- Original Message -----
>From: "Daryl Gallatin" <dgall723 at mail.dal.devry.edu>
To: <DPRGlist at dprg.org>
Sent: Friday, December 20, 2002 6:58 PM
Subject: Re: [DPRG] thermal glue


> ok , cool. :)
>
>
> This so called "snap-on" heat sink I also got doesn't work as advertised.
>
>
>
> >>> MIKE DODSON <MDODSON at MA.ATTBBS.COM> 12/20/02 16:02 PM >>>
> I use  OMEGABOND 101. I will give you some.  You can look up the  specs
> at OMEGA ENGINEERING, INC.
>
> Mike Dodson
>
> Daryl Gallatin wrote:
>
> >Will this thermal glue work for a glue on Heat sink for the TI SN754410
H-Bridge driver. Darn thing   overheats in about 30 secs with only small 6V
DC motors
> >and I'm pulsing the motors at 50hz
> >
> >
> >http://www.1coolpc.com/adhesive.htm
> >
> >
> >Mouser, Jameco  and digikey don't seem to sell the glue, though they do
sell the glue on heatsink.
> >Neither does radioshack
> >
> >I also have a snap on heatsink, but its not as easy to get on. Looks like
the snap may end up touching all the pins
> >
> >
> >Thanks
> >
> >DAryl
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> >
> >
> >
> >
>
>
>
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