Hi,
Thanks for the replys, I have removed all the wires from the motor except the positive and negative. The motor runs fine during normal operation via the mosfet, I am planning to build 100 plus of these so not sure a light bulb would be a good idea. I will use that trick for fault finding in the future to save changing fuses/ mosfets all the time.
I was thinking of using a spare ADC channel on the pic to measure the voltage between the thermal fuse and the motor, if the fuse starts to heat up as it does when it trips the resistance will increase causing voltage to drop across it, this would cause the ADC to sense more voltage at that point. I could add some code to compare the ADC value to a preset value in the program, if this value was exceeded the fet would be turned off. Does any one think that I could acheive this in time to stop damage to the Fet? The whole program at the moment takes about 100ms to execute one cycle.
regards Nick