What are line voltage and phase voltage?

Answer 1

There is no such thing as 'voltage between phases'. The voltage you are referring to is the voltage between LINES -which is why it is called a 'line voltage'!

That depends on the type, voltage, and phasing of the system in question. Residential single phase service in the US is 220V between the two lines, 110V from either line to neutral.

A common 207/110V 3 phase system is 110V from line to neutral, 207V between lines. This is mostly used in industrial settings. Beyond that you really need to look at the type of system in question, and gather your information from that. This question is too open-ended to answer specifically.

Answer 2

Answer for USA, Canada and countries running a 60 Hz power supply service.

Most power lines will carry 3 phase power. Basically there is 240V (or whatever voltage your country uses) between each phase and ground, so between phase 1 and ground, there will be 240V or 120V, between phase 2 and phase 3 will be 480V or 208V.

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Answer for countries in Europe and other world areas running a 50 Hz power supply service.

Sort of. There are two ways of configuring 3-phase connections, that is star and delta. Looking at star there are two voltages available and that is line voltage and phase voltage. Line voltage (in the UK) is 400V and you will get that between any two of the three cables or indeed all 3 cables.

Phase voltage is found in any one of the three phases measured between the cable and the star point ie neutral which will eventually be connected to the earth and that will be 230V (again that is in the UK). The relationship is LINE VOLTAGE DIVIDED BY THE SQUARE ROOT OF THREE EQUALS PHASE VOLTAGE. The square root of three is 1.73 so 400 / 1.73 = 231. You can calculate the line voltage from the phase voltage by transposing thus PHASE VOLTAGE MULTIPLIED BY THE SQUARE ROOT OF THREE EQUALS LINE VOLTAGE. So 230 x 1.73 = 397.9V. The current in star configuration is always constant.

In delta the opposite is true, ie line and phase voltages are equal but the line current is different to the phase current and can be calculated in exactly the same way as star voltages. LINE CURRENT DIVIDED BY THE SQUARE ROOT OF THREE EQUALS PHASE CURRENT and PHASE CURRENT MULTIPLIED BY THE SQUARE ROOT OF THREE EQUALS LINE CURRENT.

Another Answer

It might clarify matters if we used correct terminology. The three energised conductors that connect a three-phase supply to its load are called LINE CONDUCTORS or LINES (not 'phases'!), which is why the voltage measured between any two of them are called LINE VOLTAGES (it would make no sense whatsoever to call a voltage 'between' phases a 'line voltage'!).

For a delta-connected load, the individual loads are PHASES, which is why any voltage measured across the load is called a PHASE VOLTAGE.

Note, line voltages are measured BETWEEN lines, whereas phase voltages are measured ACROSS phases!

For a delta-connected system, a PHASE VOLTAGE is numerically-equal to the LINE VOLTAGE, but we always retain the term according to where the voltage is measured.

For a wye (star)-connected load, the PHASES exist between any line conductor and the neutral. So PHASE VOLTAGES are measured between a line and the neutral.

LINES (not phases) are identified using colours, letters, numbers, or a combination of letters and numbers. For example, A-B-C, etc. PHASES are identified according to the lines they are connected to: e.g. A-B, B-C, and C-A, or A-N, B-N, and C-N. You cannot identify an individual phase using a single letter, number, etc.

Answer 3

It is voltage between Line to Line , for example say line L1,L2 and L3.This is the voltage between L1 and L2, L1 and L3, L2 and L3 respectively.

Answer

There is no such thing as a 'phase-to-phase' voltage; the correct term (as indicated in the original answer) is 'line-to-line'. If you think about it, phases are connected either in delta or in wye -so how can there possible by voltages between phases!

Answer 4

Two Phase Voltage comprises of Phase shifted electric voltage supply for specially designed two phase devices.

Two phase power uses three wires two for Current & one for Common Ground. Both current carrying wires have Phase shifted (usually by 90 degrees) current flowing through them.

Answer 5

Depends on country. In UK and Europe it's 400 volts.

Answer 6

The voltage in the middle of line and impartial is known as the stage voltage. where the voltage between two lines called the line voltage.