Many motors are designed to be operated at either of two different voltages. For example, the three-phase motors of Figure can be connected to operate on 230- volt or 460-volt electrical power. Note that two separate coils are wrapped on each electromagnet and all leads are brought out to the terminal housing on the motor. The numbering diagrams beside each motor show how to connect the coils. The lower voltage can be used when the two coils on each electromagnet are connected in parallel, and the coils are connected in series to permit use of the higher voltage. Many single-phase motors are similarly designed for dual-voltage operation. For a given power output, the current draw of the motor will be only half as large when the higher voltage is used; thus, whenever the higher voltage is available, it should be used.
Three-phase motors with dual voltage connections
