Single Phase Vs. 3 Phase Power Advantages

By Harold Debbi, eHow Contributor

 
 
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Three-phase power is a type of electric power transmission that uses three coppers wires and a neutral wire that enable it to carry higher voltage. But single-phase power transmits power to appliances that require lower voltage. Distribution, generation and transmission of power are achieved by either single-phase or three-phase power systems via alternation of currents. As a consumer, you can choose a motor with a single-phase unit or simply use a converter to change your single-phase unit into a three-phase.

1. Economical

   • In machines that need a lot of horsepower, it is more economical to use three-phase than single-phase power. This is because three-phase power can be used for both domestic and industrial, while single-phase is more economical for domestic power use. Furthermore, three-phase motors can generate more power than their single-phase counterparts in a similar motor size. This is economical in that three-phase motors use conductors with a small cross-sectional area for high power output compared with single-phase motors, which require conductors with a wide cross-sectional area. In addition, three-phase motors have three coils that enable them to deliver power constantly and at a lower cost because there are no fluctuations, as happens with single-phase motors.

   Effective Wire Use

   • For power transmission, single-phase needs two units to function, while three-phase power requires a single unit. Therefore, three-phase power can transmit alternating currents by using three coppers in a single wire unit as compared to single phase power, which requires six wires for transmission of an equivalent amount of power. This reduces the number of copper wires needed and thus reduces cost.
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   Horsepower

   • Three-phase power has higher horsepower in the same size motor as compared to single-phase. Furthermore, with a single-phase power alternator, you have one coil rotating in the magnetic field. But by using three coils, you use the magnetic field more efficiently and thus generate more power without increasing the size of the alternator.

   House Current

   • House current is electric power delivered at 120 volts. Even though three-phase motors draw less peak current, they cannot run directly on house current like their single-phase counterparts. This is because house current is single-phase. Therefore, if you require a three-phase motor on your premises, you will need special wiring from the power company. Alternatively, you can buy a phase converter to change the single-phase current into three-phase.