We have a treadmill, but the motor control and psu unit died(one unit).What I am trying to do is control the speed of the motor with preferably a 555 timer. the motor is a DC 2hp 90v rated at 20 amps. i have a few power mosfets one rated at 100v at 100 amps. We have a fwb rectifier that drops the unregulated voltage down to about 90. i think I am overthinking the driving of the motor. i thought about putting a zener regulator to supply the power to the timer circuit but am not sure about driving the mosfet and motor.