120 and 240 Volt Motor Wiring
How to Wire a Motor for 240 Volts when the Motor is Designed for 120/240 Volts for Better Efficiency.
How to Wire a 120/240 Motor for 240 Volts
This electrical question came from: Bruce , a Homeowner from Yosemite, California.
See more about Home Wiring for California
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
- Most electric motors have a wiring junction box, typically on the rear of the motor on one side. This is where the cord or conduit attaches. The junction box has a cover plate in place to protect the wiring and connections. The motor will also have a name plate with information such as the make, model, horse power rating, voltage, amperage, etc.
- If the motor has a dual voltage capability then it will state 120/240 volts, and there will be a wiring configuration or wiring connection diagram which will explain the wiring configurations for each voltage. In some cases it may be a matter of relocating two wires with spade terminals or ring tongue terminals, and then the LINE or power source wires will attach as described.
- With larger motors there may be a larger junction box with lead wires that are identified with numbers or letters which will be identified by the wiring diagram of the specific motor.
The Benefits of Wiring a Motor for 240 Volts When it is an Option
The Advantages of a 240 Volt Motor
Bruce, thanks for your question from Yosemite,CA – which is one of my favorite places to stay. I just love Yosemite! Specifically Cabin 819 in Curry Village near the Awahnee Hotel which is the absolutely best place to be for Thanksgiving or Christmas.
The advantages of wiring a 120/240 volt motor for 240 volts is as follows:
- A balanced electrical load which may save on electricity compared to an unbalanced electrical load.
- Faster starting power. 240 volt motors will have a stronger start compared to a 120 volt motor.
- Longer life may be found due to a stronger motor, where as 120 volt motors may heat up more which may affect the over all lifespan of the motor.
- Stronger performance will definitely be noticed, especially when using equipment such as a table saw etc.
- Smaller circuit wiring size may be use in some applications because a 240 volt motor requires less amperage per leg compared to the single power leg of a 120 volt motor.
- Not all electric motors may be wired for 240 volts. Consult the name plate information that is found on the motor, or consult the information from the manufacturer to see if the motor may be wired for a higher voltage.
- In most applications the wire connections or terminations will need to be changed as well to reflect the voltage that the motor will be connected to as specified by the manufacturer of the motor.
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This link is helpful as a Homeowner
How to Wire a Motor for 240 Volts