Feeder sizes are based on the amperage of the connected load. Once that is found there are tables in the electrical code book that state what the wire size is for that particular amperage.
4160 VAC three phase three-wire delta 50/60HZ electrical power
To use a single/one phase motor instead of a three phase motor is possible if you have a three phase power supply as you will only need to tap one of the three phases together with neutral and an earthwire, however to use a three phase motor instead of a single phase will require the provision of three phase power supply.
In three phase: I = (three phase VA) / (sqrt(3) x (phase to phase voltage)) for single phase: I = (single phase VA) / ((phase to neutral voltage)) keep in mine three phase VA = 3 x (single phase VA), and phase to phase voltage = 1.732 x (phase to neutral voltage) Therefore the single phase and three phase currents are the same (ie, the three phase currents are the same in all three phases, or balanced). But don't get available current and available power confused (KVA is not the same as KW).
Any where that a three phase supply distribution is needed to operate three phase equipment.
For a transformer, the turns ratio always applies between its primary and secondary windings. So the turns ratio for a three-phase transformer is the ratio of primary to secondary phase voltages, not between line voltages.
One feeder will do the job. The definition of a feeder in the electrical trade is a set of conductors that supply a source to a load. The sizing of the feeders will depend on what the load current is. The wire count of the feeder will be dependant upon whether the load is single phase or three phase.
There is software that can be downloaded to help calculate the number of turns for a three phase motor. There are also diagrams which can be found for the most frequently used calculations.
A delta-connected system is described as being a three-phase, three-wire, system, and doesn't have a neutral. But a balanced star (wye) connected load (e.g. a three-phase induction motor) doesn't actually require a neutral.
You will need to determine the power per phase, and add them up to give the total power of the three-phase load. To do this, you will need to multiply the phase-voltage by the phase current by the power factor -for each phase.
The formula you are looking for is - phase voltage/1.73 = phase to neutral voltage.
A 7.5 kW three phase load will be balanced by the manufacturer. When connected to a three phase source the line current on each phase will be equal.
If you have three adjacent houses each with a single-phase supply taken from different phases in a three-phase cable in the street, the total power is equal to the sum of the powers in each of the three phases.
output power/Rated power
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.
How much current equipments are drawing from three phases (combined or individual) is called three phase load and how much supply we are getting from source is called three phase supply. Ex. In INDIA single phase supply is 220 volt ac with neutral. So in three phase supply all RYB phases should be 220 volts ac with neutral individually. If we calculate with phase to phase than it shoulb be 415 volts ac.
if you will experience then you will know
If an air condition is single phase, then it can only be connected to a single phase source. Since any two legs of a three phase source are considered single phase, there is no conflict, except to note that the individual phases of the three phase source match the voltage requirement of the air conditioner.