Answer / max

Single Phase voltage = Phase voltage / sqroot of 3

Answer / ashok kumar

In single phase

single phase voltage =phase voltage , but in three phase
line voltage =sq. root of phase voltage (i.e V
line=1.732x240 =415 vol.)

Answer / sunny

because the voltage is measured between the two terminals
only in 3 phase we are measuring it between 2 lines that is
why it is 440 and not 660

Answer / s singh

In single phase case; 220 v is potential difference between phase and neutral, whereas in three phase case potential difference between any two phase terminals will be around 415 v. All three lines show a potential difference of aprox 220 v with respect to neutral but are but are apart from each other by an angle of 120 degree (phase difference) so will exhibit almost double potential difference between any two line terminals. So for all practical purposes potential difference between any two phase terminals will be around 415v. However for power calculations etc we multiply 415 with squareroot of 3 to get actual total line voltage which is a sine function of phase angle between them.

Answer / m.ubaidullah khan

In three phase power line, each phase is 120 degree from the other phase.therefore, when we draw a graph of phases then two phases have positive values then at the same time the third one has negative value so we can calculate and use only two phases at a time.all three phases changes their position every time so the two phase may be phases 1 &2/phases 1&3 or phases 2&3 gives the values and at the same times phase 3 or 2 or 1 will be at negative interval respectively so cannot be calculated or contribute the value. that's the reason we use 440v instead of 660v.

Answer / umesh chandra bhuyan

Answer is very simple,so don't think too much on this.we know voltage is the potential difference between two points or levels. So that it is always measured in two wires only. So that multimeter have 2 probe only.so in single phase it is potential difference between one phase (higher potential zone) and a neutral (zero potential zone).this all about phase voltage. In case of line voltage (3phase system) this is the difference between phase to phase.all 3 phases are 120' out of phase. Example-when r phase reaches its maximum y phase is just behind it but b phase is nearer to zero as it just starts.so all two phase are act as incoming and other behave as return for other two.

Hope u will satisfy........

Answer / engr.waseem

we take voltage between two phases in 3 phase system.so in three phase system voltage between two phases or simply we can say line voltage is 380 V calculated by following formula:
line voltage=square root of 3*220(phase voltage)
=380V

Answer / pete

The question is incorrect, the line voltage is not 440v, it
will be 400v if your single phase is at 230v.
Reason why its 400v is because if you put a voltmeter across
both live phase voltages, it show 400v. But you will need a
picture showing waveforms to explain it properly.

Answer / bbhanj

Voltage is nothing but potential difference, so we can take
only 2 objects if we want to measure the difference between
them. So we always measure this difference of potential
between 2 not 3.

Answer / jawad 923218471617

that is where frequency does matter, because with frequency one of the three phase become neutral after a timeperiod. so for that reason at a moment two phases are showing 440v in pakistan).

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