Almost all of the modern alternating current (AC) motors found around the house and shop are dual-voltage (110–220 volts) motors. All homes are wired with a 110V/220V service, so it is best to wire the motor for 220-volt operation whenever possible. At 220 volts, the motor will draw one-half the current it draws at 110 volts, which means it can be wired using smaller branch circuit conductors. Smaller wire is less expensive, and it is easier to install. All it takes to change a motor to operate on the higher voltage is a screwdriver and a pair of needle-nose pliers. This is an easy task anyone can perform.
Switching a Dual-voltage Motor Between Voltages
Remove the terminal block cover. This terminal block cover is usually located on the end of the motor opposite the shaft end and held in place by two screws. On larger motors, the terminal block may be located somewhere on the circumference of the motor housing.
Study the connections diagram found on the inside of the cover. The color of the internal motor leads and the way the terminals are lettered or numbered vary slightly from one manufacturer to another. The diagram on the motor's terminal block cover will be your guide. The instructions given here will be for the most common connections used.
Use the jumpers that came with the motor when switching between 110-volt and 220-volt operation and between clockwise and counterclockwise direction of rotation. Most modern dual-voltage motors are also reversible.
Using the needle-nose pliers and one of the jumper wires, connect terminals 1 and 5 together. Using the second jumper, connect terminals 2, 3 and 8 together. To make these connections, simply push the female connectors on the jumper wires over the male connectors on the terminal board using the needle-nose pliers.
Reverse the direction of rotation by reversing the jumper connections to terminals 5 and 8.
Connect the branch circuit wires, the red and black wires, to terminals 1 and 4. Make loops in the stripped ends of the wires and place the loops under the terminal nuts in a clockwise direction. Tighten the nuts down on the wires using a nut driver.
Using the two sets of jumpers, connect terminals 1, 3 and 5 together and connect terminals 2, 7 and 8 together.
Connect the black and white circuit wires to terminals 1 and 4.
Reverse connections 5 and 8 to reverse the direction of rotation.