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120 and 240 Volt Motor Wiring

Should I wire my motor for 240volt or 120volt? The advantages of wiring a volt motor for 240 volts.

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How to Wire a 120/240 Motor for 240 Volts
Electrical Question: Should I wire my motor for 240volt or 120volt?

When wiring a 120/240volt motor is there any significant difference in power consumption 120volt vs 240volt, and any lose or gain in motor longevity?

This electrical question came from: Bruce , a Homeowner in California.

Dave’s Reply:
Thanks for your electrical question Bruce .

Wiring a Motor for 240 Volts

Application: Wiring an Electric Motor.
Skill Level: Intermediate to Advanced – Best Performed by a Licensed Electrician or Certified Motor Technician.
Tools Required: Basic Electricians Pouch Hand Tools and Voltage Tester.
Estimated Time: Depends on experience with electric motors.
Precaution: Electric motors are best serviced by an experienced electrician or knowledgeable technician. Changes in the wiring of an electric motor should only be made after the electric motor circuit has been identified and turned OFF and Tagged.

Motors that are Designed for 120/240 Volts

The Advantages of a 240 Volt Motor

Wiring a 120/240 volt motor for 240 volts is as follows:


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Home electrical wiring includes 110 volt outlets and 220 volt outlets and receptacles which are common place in every home. See how electrical outlets for the home are wired.

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How to Wire a Motor for 240 Volts

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FAQs Frequently Asked Questions and Comments

6 Responses to “120 and 240 Volt Motor Wiring”
  1. Dave Rongey says:

    Old Robbins and Meyers Motor Wiring Diagram
    Hi William,
    Unfortunately I have not been able to locate a wiring diagram for your Robbins and Meyers motor.
    I would suggest visiting the Google Groups page where there is some discussion about Robbins Myers motor wiring.
    Here is the link: Google Groups Robbins Meyer motor wiring
    I hope this helps,

  2. William says:

    Need Wiring Diagram for a Robbins Myers Motor
    I have a old Robbins & Myers motor. The plate reads, 110/220, 1725 RPM, frame S204, M/S 4470, SN AC111/94.
    There is no wiring diagram. There are 6 leads, all the same color.
    They do have numbered clip, 1, 2, 3, 4, 8, 8.
    What is the connections to run on 110 volts.


  3. Dave Rongey says:

    Circuits for Two 120volt Motors

    Hi Timothy,
    Using a multi-wire 4wire circuit for two 120volt motors would depend on the type of motors that would be connected and the application. However, due to the amperage of the 120volt motors as described, and the possibility of overloading a shared neutral it would be best to install two separate circuits, one dedicated circuit for each motor.

  4. Timothy says:

    Can I Wire Two 120volt Motors to a 240volt circuit?

    What if I have two 120v motors which operate at 14amps? I cannot run them on a single 20amp circuit.However, I have a 240 volt (4 wire) circuit which can handle much more amperage. If I was to wire one pole of each motor to the neutral and the remaining pole each to a separate hot wire (Having two 120v powers from one circuit) would that power each motor and not bust the amperage limit? Also, will there be any back-EMF effects through the neutral (which is shared)?

  5. Dave Rongey says:

    Hi Ed,
    If the existing circuit is dedicated, and the amperage is within the specs of the new motor then it can be converted to be 120 volt at the panel and at the motor connections. However, you should understand that the 120 volt motor will require more amperage, and this may affect the performance of the unit. In cases such as this it is best to replace the motor with one of the same specs to make sure the unit is left in OEM condition. This may keep you out of a potential problem with the customer in the future, plus you will not have to make any wiring changes. 😉
    I hope this helps,

  6. Ed Lawlor says:

    I have a residential unit with a fan coil wired for 208/230 volt motor. I am replacing the unit with a 120 volt EC motor. Can I use the existing wiring circuit (use one leg) to power the new equipment? Did not want to increase customer costs with new 120 volt circuit home run.