electronic sawing machine foot pad

The pad is nothing but a simple variable resistor, if it directly controls the motor then it's normal for it to get hot as the pedal is burning up the extra power to make the motor run slower. You could drastically improve efficiency and low end torque by adding a PWM drive circuit for the motor controlled by the pedal resistor. If something else is overheating then the motor is probably overloaded.

thank you very much for the help. but the problem is continuing. I changed the pad and took another one from a different machine and still it is overheating and is very uncomfortable to step on when sewing

Obviously the motor is drawing too much current, it's either mechanically binding or the motor is bad. As I said earlier, the pedal is nothing but a resistor in many machines, the only thing that will cause it to overheat is too much load.