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[DPRG] thermal glue

Subject: [DPRG] thermal glue
From: Rodent daweasel at swbell.net
Date: Mon Dec 23 22:32:01 CST 2002

2-second rule -- if you can hold your finger on it for 2 seconds without
getting burned its not running too hot. Do not confuse this with the
5-second rule, which applies to food dropped on the floor.

----- Original Message -----

>   Something does still seem strange. Perhaps a definition of hot? IE, if
you
> can hold your finger on it, it's probably ok. But still, seems somewhat
> strange. The chip could possibly be toasted from the preivious miswire,
but
> may be fine. Another possible check is to connect your motor in series
with
> a meter in Amp setting (use the 10 A range or hookup if available)
directly
> to a 6 volt battery pack. Then you can load the motor a bit by causing a
> little friction against the shaft and see just how much current it pulls.
> The 754410 itself will drop about 1.2 volts itself before it gets to the
> motor, being a bipolar device.
>    About wiring a heatsink to the chip, I got the idea from New Micros on
> their premade h-bridge module using the 754410. It's their NMIH-0010 that
> has a pretty nice setup for hooking it up, complete with a wired and
thermal
> glued heatsink not shown in the picture. See it at
http://www.newmicros.com
> and click the H-Bridge button on the side.
>   Have no clue about the motor, 503 might be a Johnson or Mabuchi part
> number, don't know. If a small FA130 by Mabuchi, it is meant to run at 3
> volts, not 6, and would overheat at higher voltages (I've even burned one
> out due to this).




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