Three-Phase Line vs Phase Voltage

V_line = √3 × V_phase

Quick answer

This calculator solves V_line = √3 × V_phase for Line-to-Line Voltage. With Phase Voltage 26.4 V, the result is 45.73 V. It solves in 2 directions, so you can enter the values you have and get the one you need.

Calculator

Line-to-Line Voltage (V)
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Formula

V_line = √3 × V_phase

Description

In a balanced three-phase wye (star) connected system, the line-to-line voltage is √3 (approximately 1.732) times the phase-to-neutral voltage. This fundamental relationship arises from the 120° phase displacement between phases. In a 208/120 V system (common in North America), V_phase = 120 V and V_line = 208 V. In a 400/230 V system (common in Europe), V_phase = 230 V and V_line = 400 V. Understanding this relationship is essential for three-phase power system design, motor connections, and transformer configurations.

Variables

  • V_line — Line-to-line (phase-to-phase) voltage (V)
  • V_phase — Phase-to-neutral voltage (V)

Practical Notes

For delta connections, the line voltage equals the phase voltage (V_line = V_phase), but the line current is √3 times the phase current. Three-phase power is P = √3 × V_line × I_line × cos(φ) regardless of wye or delta connection. In a balanced system, the neutral carries zero current.

Symbols and units

Symbol Meaning Default unit Accepted units
Vline Line-to-Line Voltage V pV, nV, µV, mV, V, kV
Vphase Phase Voltage V pV, nV, µV, mV, V, kV

Step by step

  1. 1. What you know: Phase Voltage 26.4 V
  2. 2. The relation: V_line = √3 × V_phase
  3. 3. Substitute: Vphase = 26.4 V
  4. 4. Result: Line-to-Line Voltage = 45.73 V

Worked examples

Minimum range

Given: Phase Voltage 0.726 V

Result: Line-to-Line Voltage = 1.257 V

Low range

Given: Phase Voltage 7.26 V

Result: Line-to-Line Voltage = 12.57 V

Typical

Given: Phase Voltage 26.4 V

Result: Line-to-Line Voltage = 45.73 V

High range

Given: Phase Voltage 0.506 kV

Result: Line-to-Line Voltage = 0.8764 kV

Maximum range

Given: Phase Voltage 5.06 kV

Result: Line-to-Line Voltage = 8.764 kV

Solving for each variable

Solve for Line-to-Line Voltage

Phase Voltage 0.726 V → 1.257 V

Solve for Phase Voltage

Line-to-Line Voltage 0.33 V → 0.1905 V

How Line-to-Line Voltage changes with Phase Voltage

Phase Voltage (input) Line-to-Line Voltage (result)
5.81 V 10.06 V
14.53 V 25.16 V
29.05 V 50.32 V
43.58 V 75.47 V
58.1 V 100.6 V
87.15 V 150.9 V
116.2 V 0.2013 kV
0.2324 kV 0.4025 kV
0.4067 kV 0.7044 kV
0.581 kV 1.006 kV

The same result in other units

Unit Value
mV 45730
V 45.73
kV 0.04573

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Frequently asked questions

How do you calculate Three-Phase Line vs Phase Voltage?

Use V_line = √3 × V_phase. With Phase Voltage 26.4 V, Line-to-Line Voltage works out to 45.73 V.

What is the formula for Three-Phase Line vs Phase Voltage?

The formula is V_line = √3 × V_phase. In a balanced three-phase wye (star) connected system, the line-to-line voltage is √3 (approximately 1.732) times the phase-to-neutral voltage.

How do you find Phase Voltage when you know the other values?

Rearrange for Phase Voltage: with Line-to-Line Voltage 0.33 V, Phase Voltage is 0.1905 V.

What units does Three-Phase Line vs Phase Voltage use?

Line-to-Line Voltage is shown in mV, V, kV. Values are held in SI base units internally, so you can mix prefixes without converting by hand.