Single-phase current is available to residential electric customers. 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 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.
- "Wiring Simplified, 40th Edition"; Herbert P. Richter, et al.; 2002
- Reznor: Motor Full Load Amps Table
- Photo Credit Jupiterimages/Goodshoot/Getty Images
How to Reverse the Direction of a Single Phase AC Motor
Alternating current motors are either induction start-induction run, capacitor start-induction run, or capacitor start-capacitor run motors. AC motors may be single voltage...
How to Run a Three-Phase Motor on a Single Phase
Although three-phase motors run on alternating current just as single-phase motors do, they are usually powered by a polyphase system that supplies...
How to Rewire a 3 Phase Motor to a Single Phase
Industrial and commercial facilities often require the use of three-phase electrical systems because the high-voltage motors and machines used in such places...
How to Test a Single-Phase Motor
Your washing machine, your electric dryer, your refrigerator, your generator -- all these appliances work by way of a motor. And in...
How to Connect Single-Phase Electric Motors
A single-phase electric motor is fairly simple in design, when compared to a three-phase motor. They are generally fitted in smaller electrical...