Difference between Single Phase and Three Phase AC Power Supply


The AC power (alternating current) is a kind of electricity in which the flow of current is frequently changing directions. At the beginning of the 1900 year, AC power supply is used for businesses as well as homes. The system of the power supply is categorized into two type’s namely single phase power supply, as well as three phase power supply. For most industrial and businesses settings, three-phase supply is used to run the high loads, whereas homes are generally supplied by a single phase, because home appliances require less power. This article discusses the difference between single phase and three phase power supplies.

What is Phase in Electricity?

Generally, the phase in electricity is the current or the voltage among an existing wire as well as a neutral cable. Phase means the distribution of load, if a single wire is used, an additional load will occur on it & if three wires are used then loads will be separated between them. This can be called as less power for 1-phase and more power for 3-phase. If it is a 1-phase system, it includes two wires as well as if it is a 3-phase system, then it includes 3 wires (or) four wires.

Difference between Single Phase & Three Phase

Both the power systems like single phase as well as three-phase uses AC power to refer units. Because the current flow using AC power is always in the directions of alternating. The main difference between these two supplies is the reliability of delivery.

Single Phase Supply

In the field of electrical, single phase supply is the delivery of AC power by a system in which all the supply voltages change in simultaneously. This type of power supply sharing is used when the loads (home appliances) ate generally heat and lighting with some huge electric motors. When a single phase supply is connected to an AC motor doesn’t generate a rotating magnetic field, single phase motors require extra circuits for working, but such electric motors are rare over in rating of 10 kW. In every cycle, a single phase system voltage achieves a peak-value two times; the direct power is not stable.

Single Phase Waveform
Single Phase Waveform

A load with single-phase can be power-driven from a three-phase sharing transformer in two techniques. One is with the connection between two phases or with connection among one phase and neutral. These two will give dissimilar voltages from a given power supply. This type of phase supply provides up to 230V. The applications of this supply mainly use for running the small home appliances like air conditioners, fans, heater, etc.


The benefits of choosing a single phase supply include the following.

  • The design is less complex

  • Design cost is less

  • Most efficient AC power supply for up to 1000 watts

  • Single Phase AC Power Supply is most competent for up to 1000 watts.

  • Wide-range of application uses

Single Phase Supply Applications

The applications of single-phase supply include the following.

  • This power supply is applicable for homes as well as businesses.

  • Used to supply plenty of power for homes, as well as nonindustrial businesses.

  • This power supply is sufficient to run the motors up to about 5 horsepower (hp).


The three-phase power supply includes four wires such as one neutral as well as three conductors. The three conductors are away from phase & space 120º distant from each other. Three phase power supplies are utilized as a single-phase AC power supply. For the small load, 1-phase AC power supply, as well as neutral, can be chosen from the 3-phase AC power supply system. This supply is constant and not at all totally falls to zero. The power of this system can be illustrated in two configurations namely star connection (or) delta connection. The connection of star configuration is used in long-distance communication as it includes a neutral cable to the error current.

Three Phase Waveform
Three Phase Waveform

Three Phase Supply Benefits

The benefits of choosing a three-phase supply include the following.

  • Copper Utilization Reduction

  • Lessening of Security Risks for Employees

  • Labor Treatment Costs

  • The efficiency of the Conductor is Greater

  • Facility to Run High Power Loads

Three Phase Supply Applications

The applications of the three-phase supply include the following.

  • These types of supplies are used in power grids, mobile towers, data centers, aircraft, shipboard, unmanned systems, as well as other electronic loads larger than 1000 watts.

  • It is applicable to industrial, manufacturing, and large businesses.

  • These are used in power-hungry and high-density data centers.

Key Differences between Single Phase and Three Phase Supplies

The key differences between single phase and three phases include the following.

  • The definition of the single-phase power supply is, the power supplies through a single conductor

  • The definition of the three-phase power supply is, the power flows through three conductors.

  • The single-phase power supply has one distinct wave cycle whereas; three phase has three distinct wave cycles.

  • Single phase requires the single wire to connect the circuit whereas; 3-phase needs 3-wires.

  • The voltage of the single phase is 230V, whereas three phase voltage is 415V.

  • The phase name of the single phase is split phase, whereas three phase has no other name.

  • The capacity of power transfer in the single phase is minimum, whereas three phase has the maximum.

  • The connection of single phase is simple whereas in 3-phase is complicated.

  • The power failure happens in a single phase, but not occurs in three phase.

  • The loss in single phase is maximum whereas in three phase is minimum.

  • The single-phase efficiency is less whereas in three phase is high.

  • The single-phase is inexpensive whereas the 3-phase is expensive.

  • The single-phase AC power supply is utilized for home appliances and three phase power supply is used in huge industries to run heavy loads.

Thus, this is all about the difference between single phase and three phase power supplies, and a comparison chart. From the above information finally, we can conclude that with the right care in the design part of a power supply, the designer can make suitable advice for the highest efficiency & cost savings of your project. Choosing a single phase (or) three-phase system mainly depends on the power requirements of a particular application. Anyway, a well-designed component will ensure a reliable as well as robust power distribution. Here is a question for you, what is the main function of three phase and single phase power supplies?

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