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  2. Per-unit system - Wikipedia

    en.wikipedia.org/wiki/Per-unit_system

    The base value should only be a magnitude, while the per-unit value is a phasor. The phase angles of complex power, voltage, current, impedance, etc., are not affected by the conversion to per unit values. The purpose of using a per-unit system is to simplify conversion between different transformers.

  3. Mathematics of three-phase electric power - Wikipedia

    en.wikipedia.org/wiki/Mathematics_of_three-phase...

    An important property of three-phase power is that the instantaneous power available to a resistive load, = =, is constant at all times.Indeed, let = = To simplify the mathematics, we define a nondimensionalized power for intermediate calculations, =

  4. Split-phase electric power - Wikipedia

    en.wikipedia.org/wiki/Split-phase_electric_power

    The phase shift in Europe is 120°, as is the case with three-phase current. That is why we calculate 130 V × √ 3 = 225 V. A three-phase final step-down transformer is then used. One house gets phases A and B, the next house gets phase B and C, the third house gets phase A and C.

  5. Power factor - Wikipedia

    en.wikipedia.org/wiki/Power_factor

    Power Quality Analyzers, often referred to as Power Analyzers, make a digital recording of the voltage and current waveform (typically either one phase or three phase) and accurately calculate true power (watts), apparent power (VA) power factor, AC voltage, AC current, DC voltage, DC current, frequency, IEC61000-3-2/3-12 Harmonic measurement ...

  6. Power-to-weight ratio - Wikipedia

    en.wikipedia.org/wiki/Power-to-weight_ratio

    A typical turbocharged V8 diesel engine might have an engine power of 250 kW (340 hp) and a mass of 380 kg (840 lb), [1] giving it a power-to-weight ratio of 0.65 kW/kg (0.40 hp/lb). Examples of high power-to-weight ratios can often be found in turbines.

  7. Template:Convert/list of units/energy - Wikipedia

    en.wikipedia.org/wiki/Template:Convert/list_of...

    Energy; system unit code (alternative) symbol or abbrev. notes sample default conversion combinations SI: yottajoule: YJ YJ 1.0 YJ (2.8 × 10 17 kWh) zettajoule: ZJ ZJ 1.0 ZJ (2.8 × 10 14 kWh)

  8. Electric power conversion - Wikipedia

    en.wikipedia.org/wiki/Electric_power_conversion

    A power converter is an electrical device for converting electrical energy between alternating current (AC) and direct current (DC). It can also change the voltage or frequency of the current. Power converters include simple devices such as transformers , and more complex ones like resonant converters .

  9. Kilowatt-hour - Wikipedia

    en.wikipedia.org/wiki/Kilowatt-hour

    A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a non-SI unit of energy equal to 3.6 megajoules (MJ) in SI units, which is the energy delivered by one kilowatt of power for one hour. Kilowatt-hours are a common billing unit for electrical energy supplied by electric utilities.