What is the difference between single-phase and 3-phase power?

Single-phase power is:

  • Used in most homes in North America
  • Able to supply ample power for most smaller customers, including homes and small, non-industrial businesses
  • Adequate for running motors up to about 5 horsepower; a single-phase motor draws significantly more current than the equivalent 3-phase motor, making 3-phase power a more efficient choice for industrial applications
Single-phase power diagram
With the wave form of single-phase power, when the wave passes through zero, the power supplied at that moment is zero. In the U.S., the wave cycles 60 times per second.

3-phase power is:

  • Common in large businesses, as well as industry and manufacturing
  • Increasingly popular in power-hungry, high-density data centers
  • Expensive to convert from an existing single-phase installation, but 3-phase allows for smaller, less expensive wiring and lower voltages, making it safer and less expensive to run
  • Highly efficient for equipment designed to run on 3-phase
3-phase power diagram
3-phase power has 3 distinct wave cycles that overlap. Each phase reaches its peak 120 degrees apart from the others so the level of power supplied remains consistent.
Single-Phase and 3-Phase Differences

To illustrate the difference  between single-phase and 3-phase, imagine a lone paddler in a canoe. He can only move himself forward while his paddle moves through the water. When he lifts the paddle out of the water to prepare for the next stroke, the power supplied to the canoe is zero.

Now picture the same canoe with three paddlers. If their strokes are synchronized so each is separated by 1/3 of a stroke cycle, the canoe receives constant and consistent propulsion across the water. More power is supplied and the canoe moves across the water more smoothly and efficiently.

Solutions for Single-Phase Power

Single-Phase UPS System Single-Phase PDU

Solutions for 3-Phase Power

3-Phase PDU 3-Phase UPS System
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