In a wye system the voltage between any two wires will always give the same amount of voltage on a three phase system. However, the voltage between any one of the phase conductors (X1, X2, X3) and the neutral (X0) will be less than the power conductors. For example, if the voltage between the power conductors of any two phases of a three wire system is 220v, then the voltage from any phase conductor to ground will be 110v. This is due to the square root of three phase power. In a wye system, the voltage between any two power conductors will always be 1.732 (which is the square root of 3) times the voltage between the neutral and any one of the power phase conductors. The phase-to-ground voltage can be found by dividing the phase-to-phase voltage by 1.732
answer from ground and any phase
A single-phase transformer works with a single-phase supply, while a 3-phase transformer is used with a 3-phase supply. A single-phase transformer has 2 wires on the primary and secondary (ignoring taps) while a 3-phase tansformer has 3 or 4 wires on the primary and secondary.
On a step down transformer XO symbol denotes the secondary split phase grounding point. This is also where the neutral of the three wire secondary is connected. The transformer connection is known as a single phase - three wire - with one secondary winding.
Two-phase systems have not been in general use for about 100 years because they were replaced by three-phase systems worldwide. Another type of power that is still used is 'split-phase' which is a single-phase supply using a centre-tapped transformer. For example a supply transformer has a 240 v secondary with a grounded centre-tap, so that two separate 120 v live wires are connected to the property, along with the neutral. High-power appliances like cookers or aircon can be connected across the two live wires to work at 240 v. Split-phase is also used in Europe with a 460 v centre tapped transformer used to supply a relatively small remote community, with individual properties fed a 230 v supply from one or other of the two live wires plus the neutral. The advantage is that it reduces the current in the neutral wire, and if both live wires happen to supply equal currents the neutral current going back to the transformer is zero, thus reducing power lost in the wire.
'Phase' refers to a winding into which a voltage is induced in an alternator or in a transformer or motor. The voltage across a phase is known as a 'phase voltage', and the current through it is a 'phase current'.'Three-phase', means that there are three such windings in a machine, physically displaced from each other by 120 degrees, with each phase voltage is displaced by 120 electrical degrees.The term 'phase' is sometimes, incorrectly, used to describe the 'hot' wire in an electrical installation -the correct term, though, is 'line'.
Your question doesn't describe under what circumstances the transformer is being used. Normally, a two wire (hot and ground) AC voltage can only be a single phase supply. Look up the explanation of how AC current cycles on a sinewave (60Hz is 60 sinewave cycles per second). This is also known as a single phase. Coming into a standard residential house is a three wire line with two hot wires and a ground wire. The two hot wires are out of phase with each other (opposite sinewave). A standard transformer can have multiple outputs with various/same voltage. Look up how a transformer works. Without special electronic components for each output circuit, all taps will be in phase. A transformer outfitted with the special electronic components is very expensive and not for normal everyday use.
Yes
A Scott transformer converts 3-phase to 2-phase and vice versa, so if you get a Scott transformer it can convert a 2-phase supply into 3-phase for the motor. Caution: the 2-phase supply has to be a genuine 2-phase as defined, with 90 degrees phase between the two phases, and these are extremely uncommon. A Scott transformer CANNOT be used with the split-phase supply found in many US homes which have a 240 v single-phase transformer with the centre earthed and connected to a neutral wire to produce two 120 v circuits.
It is done by connecting the neutral to earth at the transformer that produces the three-phase supply. If the three phase wire supply equal currents, there is no current in the neutral wire and its whole length stays at earth potential, but if there is current in the neutral it produces a small voltage on the neutral at places away from the transformer.
Wire sizing of a feed conductor is based on the amperage that a device draws. To calculate amperage from KVA a voltage of the supply has to be stated. Without this voltage and whether the transformer is single or three phase an answer can not be given.
A single-phase transformer works with a single-phase supply, while a 3-phase transformer is used with a 3-phase supply. A single-phase transformer has 2 wires on the primary and secondary (ignoring taps) while a 3-phase tansformer has 3 or 4 wires on the primary and secondary.
On a step down transformer XO symbol denotes the secondary split phase grounding point. This is also where the neutral of the three wire secondary is connected. The transformer connection is known as a single phase - three wire - with one secondary winding.
The normal way is to use a transformer with a 3-wire primary and a 4-wire secondary. In the UK that happens at electricity substations for example where the 11 kV supply comes in on 3 wires and goes out at to users at 240 v with three phase wires and a neutral.
Two-phase systems have not been in general use for about 100 years because they were replaced by three-phase systems worldwide. Another type of power that is still used is 'split-phase' which is a single-phase supply using a centre-tapped transformer. For example a supply transformer has a 240 v secondary with a grounded centre-tap, so that two separate 120 v live wires are connected to the property, along with the neutral. High-power appliances like cookers or aircon can be connected across the two live wires to work at 240 v. Split-phase is also used in Europe with a 460 v centre tapped transformer used to supply a relatively small remote community, with individual properties fed a 230 v supply from one or other of the two live wires plus the neutral. The advantage is that it reduces the current in the neutral wire, and if both live wires happen to supply equal currents the neutral current going back to the transformer is zero, thus reducing power lost in the wire.
It is very simple. Just interchange any two phase wires. i.e. Y and B ( or ) R and B ( or ) R and Y for example Stop the supply. keep R phase wire as it is and disconnect B phase wire and Y phase wire. Connect B phase wire to the Y phase motor stud and Y phase wire to the B phase motor stud. Now give the supply, now motor revolves in opposite direction to the earlier.
'Phase' refers to a winding into which a voltage is induced in an alternator or in a transformer or motor. The voltage across a phase is known as a 'phase voltage', and the current through it is a 'phase current'.'Three-phase', means that there are three such windings in a machine, physically displaced from each other by 120 degrees, with each phase voltage is displaced by 120 electrical degrees.The term 'phase' is sometimes, incorrectly, used to describe the 'hot' wire in an electrical installation -the correct term, though, is 'line'.
For a three-phase, four-wire, system, single-phase loads can be connected between any pair of line conductors. For a three-phase, four-wire, system, single-phase loads can be connected between any pair of line conductors, or between any line conductor and the neutral conductor. The choice depends on the voltage requirements of the load.
Your question doesn't describe under what circumstances the transformer is being used. Normally, a two wire (hot and ground) AC voltage can only be a single phase supply. Look up the explanation of how AC current cycles on a sinewave (60Hz is 60 sinewave cycles per second). This is also known as a single phase. Coming into a standard residential house is a three wire line with two hot wires and a ground wire. The two hot wires are out of phase with each other (opposite sinewave). A standard transformer can have multiple outputs with various/same voltage. Look up how a transformer works. Without special electronic components for each output circuit, all taps will be in phase. A transformer outfitted with the special electronic components is very expensive and not for normal everyday use.