For the info. of everybody.....
the 3-phase system is definitely use in large commercial & industrial plant that uses large equipment/apparatus, like motors powered by more than 230v supply.
However, single-phase system was commonly used in residential, which uses 230V or 110V equipment/apparatus, also considered as light load....
Daryll Jan of Sorsogon City, Philippines (10yrs. old, Grade V)
POWER OF 3 PHASE SYS = 3 TIMES OF THE POWER FOR 1 PHASE SYSTEM
For a given load, a three-phase system requires around 75% of the volume of copper required by a corresponding single-phase system and, so, is more economical. A three-phase supply also delivers power more or less continuously, whereas a single-phase supply delivers power in pulses. Finally, three-phase motors are self-starting and physically smaller than single-phase machines of the same power rating.
cheap,quiet,long lifetime for motor
There are several advantages of 3-phase power over single phase power. First, with 3-phase power, more power can be transferred with the same amount of wire (meaning the amount of copper used in all of the conductors transferring that power) as with single or 2-phase power. Also, power is transferred more "evenly" with 3-phase power because the "next peak" is closer than it is with single and 2-phase power. The 3-phase motors run more smoothly than those run on fewer phases. Also, there are motor design considerations (one being control of the direction of rotation) regarding the motor that make 3-phase power more attractive. Use the link to the Wikipedia article on 3-phase power and skim it. It isn't long and it is quite readable.
On a three phase system you have incorporated into it a potential of three single phase systems. A-B, B-C, C-A. Any two legs of a three phase system can be used as a single phase load. On a three phase system, be it a motor or a service, if one of the legs drops out for what ever reason, the remaining two legs are known as single phase. This is how the terminology became single phasing. As a side note a motor will run in a single phase condition, it just will not start. In motor control, a single phase condition is prevented by the use of overload heaters on all three voltage legs.
You need to match the UPS to the service. If it is three phase you need a three phase UPS, and vice versa for single phase. It isn't a case of being better, it is a situation where you need to match your application.
The primary advantage is that, for a given load, a three-phase system requires less copper for tranmission/distribution than an equivalent single-phase system would require. Other advantages include the fact that three-phase machines are smaller than single-phase machines of similar rating.
Very complicated, first you have to rectify your single phase to get DC then you need a 3 phase sine wave signal, that can be generated with a MCU, to drive three pairs of push pull amplifiers that is connected to a three phase transformer's primary windings and you have your output at the secondary
Single phase inherently requires less equipment (it's cheaper). Three phase motors are more efficient than single phase.
For a given load, a three-phase system uses less volume of copper (therefore is more economical) than a corresponding single-phase system, while supplying approximately-constant power. From the users' point of view, three-phase motors are self-starting and more compact than the equivalent single-phase motor.
Over all losses are less in three phase AC system compared to 1 phase. For a given load (KW) 1 phase system would draw more current
By having a transformer with 3 phase input and single phase out put
A heterogeneous mixture, such as a salad with different vegetables, cannot be considered a single phase. It contains distinct regions with different compositions and properties, making it a multi-phase system.
3 phase system has more power than a single phase system
A 3 phase system needs only to use 3 or 4 conductors, as against 6 conductors if it were 3, single phase conductors The amount of copper used in a 3 phase is much less than what would be needed in a single phase system carrying the same current, this reduction in copper allows for weight reduction and cost savings. The power losses in a 3 phase system are much less than in a single phase system.
For a given load, a three-phase system requires around 75% of the volume of copper required by a corresponding single-phase system and, so, is more economical. A three-phase supply also delivers power more or less continuously, whereas a single-phase supply delivers power in pulses. Finally, three-phase motors are self-starting and physically smaller than single-phase machines of the same power rating.
cheap,quiet,long lifetime for motor
3 Phase system is for industrial use and 1 phase is for house hold application