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In electrical engineering, three-phase electric power systems have at least three conductors carrying alternating voltages that are offset in time by one-third of the period. A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas, as symbolically it is similar to the letter 'Y').
A three-phase motor is more compact and less costly than a single-phase motor of the same voltage class and rating, and single-phase AC motors above 10 hp (7.5 kW) are uncommon. Three-phase motors also vibrate less and hence last longer than single-phase motors of the same power used under the same conditions. [32]
Inverters that target commercial applications are available for 208, 240, 277, 400, 480 or 600 VAC and may also produce three phase power. Peak efficiency: The peak efficiency represents the highest efficiency that the inverter can achieve. Most grid-tie inverters on the market as of July 2009 have peak efficiencies of over 94%, some as high as ...
Most of the world uses 50 Hz 220 or 230 V single phase, or 400 V three-phase for residential and light industrial services. In this system, the primary distribution network supplies a few substations per area, and the 230 V / 400 V power from each substation is directly distributed to end users over a region of normally less than 1 km radius.
An American Rotary Phase Converter with a Transformer. A phase converter is a device that converts electric power provided as single phase to multiple phase or vice versa. The majority of phase converters are used to produce three-phase electric power from a single-phase source, thus allowing the operation of three-phase equipment at a site that only has single-phase electrical service.
3-phase inverter switching circuit showing 6-step switching sequence and waveform of voltage between terminals A and C (2 3 − 2 states) To construct inverters with higher power ratings, two six-step three-phase inverters can be connected in parallel for a higher current rating or in series for a higher voltage rating.
Single-phase inverter: This type of inverter consists of two legs or two poles. (A pole is connection of two switches where source of one and drain of other are connected and this common point is taken out). Three-phase inverter: This type of inverter consists of three legs or poles or four legs (three legs for phases and one for neutral).
The transform applied to three-phase currents, as used by Edith Clarke, is [2] = = [] [() ()]where () is a generic three-phase current sequence and () is the corresponding current sequence given by the transformation .