New, Rheem central air conditioners' condenser fan motors come with a five-wire setup. The older condenser fan motors had only three wires. You can connect a five-wire fan motor to an older three-wire fan motor only if you buy a new capacitor. The new capacitor will replace your old capacitor, and provide you with the connections for the two extra wires.
Install the new capacitor. You must buy a new capacitor that is compatible with your new Rheem 5-wire condenser fan motor. The fan motor's manual will tell you which capacitor is compatible.
Connect the brown wires to the new capacitor. Connect them to the two golden screws on top of the capacitor. Secure in place with the screwdriver.
Connect black fan wire to the black hot wire. You connect the fan wire motor in the terminal where the line wires connect, this is called the contactor. Screw the wire in place with the screwdriver.
Connect the orange wire to the contactor. Secure it in the second terminal with your screwdriver.
Connect the white wire to the contactor. Connect the white wire to where the neutral wire from the line connects. Secure it in the contactor with your screwdriver.
Turn off circuit breakers before working on the wiring.