If you want to have a 3-phase service with a neutral then one way to get it is to connect the incoming three phases of a standard 3-phase service to a transformer whose secondary windings are connected in what is called a "star" (also known as a "Y" or "wye") configuration which has a neutral point at the center of the "star" or "Y".
Then, to get a single-phase service, you can use just one phase and the neutral. This results in about half the voltage - actually it's 1 / 2./'3 (1 divided by the square root of three) - that you'd get across any two phases of the incoming 3-phase service.
Note
A three phase service on its own does not have a neutral line. The voltage difference is measured between the phases. (No voltage can be measured between any of the phase lines and a neutral because there is no neutral line.)
Any electrical equipment which uses a 3-phase service exactly as it is delivered by the power generator / utility - that is, without a neutral line - are connected in what is known as "delta" connection.
Only one neutral conductor is typically in a 3 phase panel.
Yes, you can reduce the neutral in a three phase system. you must figure the unbalanced current the neutral will carry and also make allowances for any harmonics that may be present.
A single-phase cable will have a line and a neutral conductor and, possibly, but not necessarily, an earth (ground) conductor. A high-voltage three-phase cable will have three line conductors. A low-voltage three-phase cable is likely to have three line conductors and a neutral conductor.
A 3 phase motor does not require a neutral conductor because the impedances that make up the stator coils are of equal magnitude and it is what is known as a balanced 3 phase load. If the loads of a wye connected 3 phase system were unbalanced, i.e. the load currents in each of the 3 phases are different, then the unbalanced currents would require a return path to the service transformer via a neutral conductor. The neutral conductor is the transformer centre tap and is usually earthed locally. ANOTHER ANSWER The impedance of each phase winding of a three phase motor is identical (we call it a 'balanced load'). For a star (wye) connected motor, the phasor sum of three identical phase currents is zero, so no current will flow through a neutral, so a neutral isn't required. For a delta-connected motor, there is no provision for a neutral.
No, this voltage appears ACROSS individual phases, or BETWEEN a line conductor and the neutral
Only one neutral conductor is typically in a 3 phase panel.
no
Yes, you can reduce the neutral in a three phase system. you must figure the unbalanced current the neutral will carry and also make allowances for any harmonics that may be present.
A ground, or earth, conductor is never included in the conductor count. So, a three-phase, three-wire, system has three line conductors, whereas a three-phase, four-wire system, has three line conductors and a neutral conductor.
A single-phase circuit has one live conductor and one neutral conductor, typically used for residential applications. A three-phase circuit has three live conductors and one neutral conductor, used for higher power industrial applications due to its ability to provide a more balanced power distribution.
A single-phase cable will have a line and a neutral conductor and, possibly, but not necessarily, an earth (ground) conductor. A high-voltage three-phase cable will have three line conductors. A low-voltage three-phase cable is likely to have three line conductors and a neutral conductor.
A 3 phase motor does not require a neutral conductor because the impedances that make up the stator coils are of equal magnitude and it is what is known as a balanced 3 phase load. If the loads of a wye connected 3 phase system were unbalanced, i.e. the load currents in each of the 3 phases are different, then the unbalanced currents would require a return path to the service transformer via a neutral conductor. The neutral conductor is the transformer centre tap and is usually earthed locally. ANOTHER ANSWER The impedance of each phase winding of a three phase motor is identical (we call it a 'balanced load'). For a star (wye) connected motor, the phasor sum of three identical phase currents is zero, so no current will flow through a neutral, so a neutral isn't required. For a delta-connected motor, there is no provision for a neutral.
A three phase system will have 3 phase branch circuits and no neutral.
None.In standard single phase wiring there are 3 wires: hot (black), neutral (white), and ground (green). Each has a different purpose and none can be used for any other purpose.
No, this voltage appears ACROSS individual phases, or BETWEEN a line conductor and the neutral
From line-to-line (any two of the three leads) voltage or 'line voltage', the voltage is 208 V. The line-to-neutral (one of the three leads and the neutral conductor), or 'phase voltage', is 120 V.
On a Delta 3-phase you connect the single phase loads between pairs of the 3-phases. Warning both sides of these loads will be hot! You may want to use 3 isolation transformers so that the real loads have a neutral line.On Y 3-phase you connect the single phase loads between one of the 3-phases and neutral.In each case to balance the loads, try to put similar loads on each phase (or pair of phases).