What Is the Biggest Size Single-Phase Motor?

Single-phase current is available to residential electric customers.

Single-Phase Current

Single phase electric motors operate tools and appliances.Single phase electric motors operate tools and appliances.
Appliance and tool motors that operate on a home's electrical system are necessarily single-phase motors for this reason. Single-phase motors are inherently inefficient and therefore limited in horsepower.

Single-phase alternating current rises from a negative voltage to a positive voltage before falling back to a negative voltage again, repeating the cycle 60 times every second. This type of electrical power is commonly supplied to residential and commercial buildings because it is well-suited to light electrical loads for lighting and small to medium appliances and tools.

Single-Phase Motors

Single-phase motors become increasingly inefficient as they grow larger and require higher currents to operate. The limitations of residential electrical power coupled with the inefficiency of single-phase motors makes them impractical for higher power applications. Motor manufacturers make small, single-phase motors for residential and commercial use, and large three-phase motors for industrial use.

Large Single-Phase Motors

The largest single-phase motors suitable for residential use top out at 10 horsepower. A few commercial applications may be found for higher voltage single-phase motors at up to 15 horsepower, but these are rare and require 480 volts of single-phase current to operate. Three-phase motors are much more efficient and manufacturers make them in ratings of hundreds of horsepower.

About the Author

Michael Logan is a writer, editor and web page designer. His professional background includes electrical, computer and test engineering, real estate investment, network engineering and management, programming and remodeling company owner. Logan has been writing professionally since he was first published in "Test & Measurement World" in 1989.