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Posted by Thomas A. Frank.   [PICTURE: SAME | NEW | HELP]


Engineer on team #121, The Islanders/Rhode Warrior, from Middletown (RI) High School and Naval Undersea Warfare Center.

Posted on 6/18/99 2:50 PM MST


In Reply to: Don't we all... posted by Joe Johnson on 6/16/99 6:36 PM MST:



: I really regret that we didn't get Globe to donate a flavor of motor with a PTC (i.e. a type of self resetting thermal fuse) inside.

: I recommend to FIRST that they get a properly sized PTC and require that everyone put them inline with the Globe motors.

: I know in our case, I would much rather have had to spend a little time cooling down the motors every once in a while than to be allowed to run them so hot that they fail.

: We have blown a few because a mistake in our controller code was keeping them slightly on at all times. In a long practice they got way too hot to touch.

: PTC's next year...


Hi Joe;

Keep your PTC's to yourself! I hate the $@#$@#$@#$@# things - I'd much rather spend the effort on the front end making sure I don't run the motor
to destruction, than add another point of failure/inconvienience.

I don't want some piece of hardware telling me that no, the motor won't generate anywhere near full power right now, no matter how
desparately you might want it. I prefer to allow the human to make the decision to risk killing the motor rather than giving up at some point.
Maybe it's a part of our business philosophy, where we put a switch on the box marked 'Battle Short' that bypasses all the circuit breakers and
related safety devices to keep the unit operating no matter what (or it gets toasted, but at least you got to try!).

Fix the software, that's the 'better' way...

The PTC's have been nothing but a pain as far as I'm concerned. I was pleased to see that the Globe motors didn't have them.

Tom Frank