In three-phase calculations, what is the purpose of the factor 1.73?

In three-phase calculations, what is the purpose of the factor 1.73?

• A. It corrects for efficiency losses
• B. It converts kilovolt-amps to watts
• C. It represents the square root of 3 and relates line-to-line voltages to phase voltages
• D. It adjusts for temperature effects on resistance

Answer: (C)

In a balanced three-phase system, the three phase voltages are 120 degrees apart. The voltage measured between two lines (line-to-line) is the vector difference between two of those phase voltages, and its magnitude works out to be √3 times the phase-to-neutral voltage. That is where the 1.73 factor comes from. It lets you convert between line quantities and phase quantities, and it appears in important formulas like P = √3 V_L I_L cosφ and V_L = √3 V_Ph when the system is wye-connected. So, the purpose of the factor is to relate line-to-line voltages to the corresponding phase voltages.

In a balanced three-phase system, the three phase voltages are 120 degrees apart. The voltage measured between two lines (line-to-line) is the vector difference between two of those phase voltages, and its magnitude works out to be √3 times the phase-to-neutral voltage. That is where the 1.73 factor comes from. It lets you convert between line quantities and phase quantities, and it appears in important formulas like P = √3 V_L I_L cosφ and V_L = √3 V_Ph when the system is wye-connected. So, the purpose of the factor is to relate line-to-line voltages to the corresponding phase voltages.