Heater Catalog - Watlow

Reference DataEquationsTypical 3-Phase Wiring Diagrams andEquations for Resistive HeatersDefinitionsFor Both Wye and Delta(Balanced Loads)V p = Phase voltageV L = Line voltageI p = Phase currentI L = Line currentR = R 1 = R 2 = R 3 == Resistance of each branchW = WattageWye and Delta EquivalentsW DELTA = 3 W WYEW ODELTA = 2 /3 W DELTA3-Phase Delta (Balanced Load)R 1R 3I LI LR 2I PV PV LEquations For Delta OnlyI P = I L /1.73V P = V LW DELTA = 3(V L 2 )/RW DELTA = 1.73 V L I LW OWYE= 1 /2 W WYE3-Phase Wye (Balanced Load)R 1R 2I PV PR 3V L3-Phase Open DeltaI L01I P03V LI P01I LI L02Equations For Wye OnlyI P = I LV P = V L/1.73W WYE = V L2 /R = 3(V P2 )/RW WYE = 1.73 V LI L3-Phase Open Wye (No Neutral)Equations For Open Delta OnlyV P = V LI PO1 = I PO3 = I LO2I LO3 = 1.73 I PO1W 0DELTA = 2 (V L 2 /R)R 1R 2I POV POV LI LOEquations For Open Wye OnlyI PO = I LOV PO = V L/2W 0WYE = 1 /2 (V L2 /R)W 0WYE = 2 (V PO2 /R)W 0WYE = V LI LO550WATLOW ®