Eaton Power Xpert Solar 1500 User Manua

Glossary64 Power Xpert Solar 1500/1670 kW Inverter MN141001EN—October 2014 www.eaton.comTerm Abbreviation / Definitionvar . . . . . . . . . . . . . . . . . . volt-ampere reactive (var).A unit used to measure reactive power in an AC electric power system. Reactive power existsin an AC circuit when the current and voltage are not changing at the same time. The correctsymbol is var and not Var, VAr, or VAR, but all 3 terms are widely used.Vars may be considered as either the imaginary part of apparent power, or the power flowinginto a reactive load (e.g., inductive loads such as motors or capacitive loads such as switchingpower supplies), where voltage and current are specified in volts and amperes. The twodefinitions are equivalent.For utility AC distribution sinusoid-currents and voltages at the same frequency, reactive powerin vars is the product of the RMS voltage and current, or the apparent power, multiplied by thesine of the phase angle between the voltage and the current. The reactive power Q (measuredin units of volt-amperes reactive or var), is given by:Q = Vrms Irms sin (f)where f is the phase angle between the voltage and the current.Only effective power, the actual power delivered to or consumed by the load, is expressed inwatts. Imaginary power is properly expressed in volt-amperes reactive and does notaccumulate Watts on a utility-billing power meter.WYE . . . . . . . . . . . . . . . . . Star-connection.Line-to-Line and Line-to-Neutral ConnectionsA type of 3-phase transformer with a central neutral connection. The neutral is equallyreferenced to the 3-phases (i.e., Line-to-Neutral).3-Phase . . . . . . . . . . . . . . Electrical System consisting of 3 lines.See SymbolsEach line is 120-electrical-degrees apart, measured line-to-line.Typically rated at 208 V and 480 V for commercial services.208 V L–L has 120 V L–N … 480 V L–L has 277 V L–N.Note:1 Reference citation: NAPF 70: National Electric Code 2011.