Pull the fuse or trip the circuit breaker that supplies electrical power to the attic. If the attic fan uses a power cord instead of being wired to an electrical socket, pull the cord out of the AC outlet. Remove the screws surrounding the attic fan with a Phillips screwdriver. Pull the back grille off the attic fan with your hands. Place the grille aside.
Locate the drive belt that is attached to the motor shaft's hub at one side of the motor. Pull the drive belt's loop off the hub -- the belt must be slightly stretched to accomplish this. Pull the loop at the other end of the belt off the hub at the back end of the fan blade assembly. Place the drive belt aside for now.
Remove the screws surrounding the motor with the Phillips screwdriver. The screws are in the brackets attached to each side of the motor. Pull the motor part of the way out of the fan. Loosen the screws on the two electrical contacts on the back end of the motor with the Phillips screwdriver.
Unwind the two electric wires from around the screws. Pull the motor completely out of the fan, and dispose of it in an eco-friendly way.
Shake the can of lubricating spray for two seconds. Spray a burst of lubrication at the motor shaft's hub. Loosen the screws on the two electrical contacts on the back end of the replacement motor with the Phillips screwdriver. Wind the end of the two wires around the screws, in the same manner as they were wound around the defective motor. Tighten the screws.
Place the motor in the fan in the position that the defective one occupied earlier. Attach the screws to hold the motor in place.
Loop an end of the drive belt around the hub at the back end of the fan blade assembly. Stretch the belt so that you can loop the other end around the hub attached to the motor shaft. Place the grille back on the attic fan. Reattach the screws. Return power to the attic fan.