simple electronic way. Have a magnet on the rotating part. Place a reed
switch near enough that it closes every time the magnet comes by. Have a
timer you set to two seconds. Reset the timer when you presss "start", and
every time the reed switch is closed by the magnet. You can make this timer
from a 555 chip, or just buy a timer. If the timer expires, drop out a
relay to de-energize the motor.



"Buerste" wrote in message
...
Imagine a simple fractional hp DC gearmotor with a torque limiter or
torque limiting clutch that powers a small machine at 60 or so RPM. Lets
say the machine jams and the torque limiting device kicks out. How can I
cheaply, easily sense this condition and turn off the motor?

This is a personal project and when I get it running it will amaze and
astound!