There are different kinds of protection for different type of motors such as: thermal (direct thermal measurement such as PTC’s (positive temperature coefficient) or NTC’s (negative temperature coefficient)), current measurement and related calculations, electronics, micro logics etc that their weakness point is they cannot predict the fault and also is not sufficient as much as human’s life worth.
My idea is besides of ordinary protections, by measuring and analyzing the smell
(in respect to temperature and smell algorithms) risen from motor, we can detect
and predict the motor behavior and also probable damages before it get late on the
ground for planes motors.