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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.
Wiki User
∙ 13y ago
Wiki User
∙ 11y agoBy neutral I'll assume you mean the wire with 0V on it.
This is needed to get 240V out of the supply. Connect your voltmeter between either Line 1, Line 2 or Line 3 and the 0V and you will get a fluctuating +240V to -240V.
If you only want 415V, then you connect your voltmeter between two of the live phases and you will get a fluctuating +415V to - 415V. The 0V wire is not used in this case, effectively one of the phases becomes the "neutral".
See related links below.
Wiki User
∙ 11y agoIf the 3-phase system is perfectly balanced, with equal currents in all three phases, no current flows in the neutral and it would make no difference to take it away.
But in many cases the three phases do not carry identical currents, and some residual current flows in the neutral.
Answer for UK, Europe and countries running a 50 Hz supply service.
As an example, in the UK, houses along a street all have a single phase 240 v supply, taken from a 3-phase cable going along under the street (or on poles).
The three live phases are red, yellow and blue. One house might use red and neutral, the next one yellow and neutral, and the next one blue and neutral for their supplies.
Different houses use different phases and you end up with a large enough number of houses presenting a balanced load.
But a small number of houses can be unbalanced, say if no. 1 is running a power shower (30 amps), no. 3 is only doing the ironing (4 amps), and no. 5 is away on holiday (0 amps). That is when the neutral wire is needed to maintain the right voltage on all three live phase wires for the three houses.
Wiki User
∙ 12y agoIt is generally not needed for most 3 phase motors. It sometimes is provided for equipment that requires a path to the neutral bar for proper operation.
Wiki User
∙ 12y agoIn the case of a three-phase, wye- or star-connected supply, a neutral would be unnecessary if the load were to be perfectly balanced.
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What is the voltage for each leg on a 480v 3-phase pannel phase to neutral?
Only one neutral conductor is typically in a 3 phase panel.
Can the neutral conductor be downsized in a 3 phase electrical system?
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.
How many wire or core in three phase electrical connection and single-phase electrical connection?
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.
Why neutral not conect in 3phase motor?
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.
The output voltage between phases of ac 3 phase supply is 240V?
No, this voltage appears ACROSS individual phases, or BETWEEN a line conductor and the neutral
What is the voltage for each leg on a 480v 3-phase pannel phase to neutral?
Only one neutral conductor is typically in a 3 phase panel.
Is there a neutral conductor in a 3 phase 4 wire wye system?
no
Can the neutral conductor be downsized in a 3 phase electrical system?
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.
How many wires are in a 3 phase circuit?
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.
How many wire or core in three phase electrical connection and single-phase electrical connection?
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.
Why neutral not conect in 3phase motor?
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.
What is the code ruling in the US on 3 phase branch circuits and the neutral?
A three phase system will have 3 phase branch circuits and no neutral.
What is substitute of neutral wire?
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.
The output voltage between phases of ac 3 phase supply is 240V?
No, this voltage appears ACROSS individual phases, or BETWEEN a line conductor and the neutral
What voltage should 208 3 phase leads read?
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.
Why do you balance single phase loads across a 3-phase supply system?
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).
What is line voltage in star connection?
Phase to phase voltage is 1.732 (the square root of 3) times the phase to star point (neutral) line voltage.e.g. if the line voltage is 220Vphase voltage = 1.732x220 = 380V (approx)Additional AnswerYou might also like to know that the line voltage leads the phase voltage by 30 electrical degrees. And, incidentally, the correct expressions are 'line-to-line' not 'phase-to-phase', and 'line-to-neutral' not 'phase-to-neutral' (think about it, a line voltage is measured from the junctions between adjacent phases, so they cannot be 'phase to phase'!)
