Blowing 60 Amp fuse

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Posted by Allen Smith, Engineer on team #7, Knights, from Parkville High School and Black & Decker/AAI/Raytheon.

Posted on 3/20/99 2:27 PM MST


In Reply to: Blowing 60 Amp fuse posted by Joe Johnson on 3/19/99 5:17 PM MST:



We were your partners when you blew that fuse in the quarter-finals at Philly
so I have been thinking about this problem also. First, I am amazed at the
traction you get from your wheels. Do you have some secret treatment to
keep them from slipping? If your wheels would slip you would of course
have less pulling power but the slipping would act as a "fuse" keeping
the motor operating in an acceptable region. This is what happens with our
robot and we have yet to blow a fuse or burn up a speed controller. A
possible solution, and I'm just speculating here and would love comments,
would be to have 5 to 10 feet of coiled wire between your ground bus and
your battery acting as a current monitoring shunt. Connect the ground bus
that is on the far side of the coil of wire from the battery to an analog
input on the controler, assuming you have a few tens of milliohms in that
coil your controller should be able to sense the total current flowing
and do something about it like light a warning led or cut back on the PWM
signal going to the motors. It would be nice to have a filter on the signal
going into the controller and a zener to clamp it to no more than 5 volts
but with only kit parts I don't think this is possible.