3 Phase Delta/Wye Calculator
Three phase power is typically delivered in two different forms, the Delta and Wye (Star) configurations. Both get their names from the physical characteristics of the configuration and the Greek letters that they resemble. The Delta configuration features a high starting torque and a inherent fault tolerance as an open element will not affect the others (although the phase current will be higher). The Wye configuration uses less starting current and is typically used for power transmission. It also uses a fourth wire.
Delta Configuration Formulas
Wye Configuration Formulas
LINE VOLTAGE (Vline)
LINE CURRENT (Iline)
PHASE VOLTAGE (Vph)
PHASE CURRENT (Iph)
APPARENT POWER (S)
REAL POWER (P)
REACTIVE POWER (Q)
Power factor only valid from -1 to 1
Real power must be greater than 0
The three phase calculator uses the power triangle in which Real Power is expressed in Watts (W). Reactive
Power is expressed in Reactive Volt Amps (VAR). Apparent Power is expressed
in Volt Amps (VA). With power in an AC system there is always an inductive or reactive
aspect to the circuit which causes the current to lead or lag the voltage. The actual power draw from a
circuit takes this into consideration and is described as Apparent Power.
Three phase power means that each phase is 120 degrees out of phase with each other. The voltage between two
lines is the line voltage. Three phase power is typically used for induction motors (as it helps reduce the
need for a starter capacitor) and heavy loads because it is usually more economical that two-wire/single
phase. Voltage availability is regional and is 50 or 60Hz. In both Delta and Star (or Wye) configurations the
calculations for real/active, apparent, and reactive power are the same. Phase and line current are equal in
the Star (or Wye) configuration, and the line voltage is equal to √3 times the phase voltage. In Delta
configuration line and phase voltage are equal and line current √3 times the phase current.
