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  2. Mathematics of three-phase electric power - Wikipedia

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

    A delta system arrangement provides only one voltage, but it has a greater redundancy as it may continue to operate normally with one of the three supply windings offline, albeit at 57.7% of total capacity. [1] Harmonic current in the neutral may become very large if nonlinear loads are connected.

  3. Transformer - Wikipedia

    en.wikipedia.org/wiki/Transformer

    The transformer winding voltage ratio is equal to the winding turns ratio. [6] An ideal transformer is a reasonable approximation for a typical commercial transformer, with voltage ratio and winding turns ratio both being inversely proportional to the corresponding current ratio. The load impedance referred to the primary circuit is equal to ...

  4. Scott-T transformer - Wikipedia

    en.wikipedia.org/wiki/Scott-T_transformer

    Assuming the desired voltage is the same on the two and three phase sides, the Scott-T transformer connection (shown right) consists of a centre-tapped 1:1 ratio main transformer, T1, and a √ 3 /2(≈86.6%) ratio teaser transformer, T2. The centre-tapped side of T1 is connected between two of the phases on the three-phase side.

  5. Energy conversion efficiency - Wikipedia

    en.wikipedia.org/wiki/Energy_conversion_efficiency

    For example, an ideal fuel cell operating at a temperature of 25 °C having gaseous hydrogen and gaseous oxygen as inputs and liquid water as the output could produce a theoretical maximum amount of electrical energy of 237.129 kJ (0.06587 kWh) per gram mol (18.0154 gram) of water produced and would require 48.701 kJ (0.01353 kWh) per gram mol ...

  6. 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.

  7. Per-unit system - Wikipedia

    en.wikipedia.org/wiki/Per-unit_system

    The ratio of the voltage bases on either side of a transformer is selected to be the same as the ratio of the transformer voltage ratings. With these two rules, a per-unit impedance remains unchanged when referred from one side of a transformer to the other. This allows the ideal transformer to be eliminated from a transformer model.

  8. Electric power transmission - Wikipedia

    en.wikipedia.org/wiki/Electric_power_transmission

    Should an ideal transformer convert high-voltage, low-current electricity into low-voltage, high-current electricity with a voltage ratio of (i.e., the voltage is divided by and the current is multiplied by in the secondary branch, compared to the primary branch), then the circuit is again equivalent to a voltage divider, but the wires now have ...

  9. Superconducting magnetic energy storage - Wikipedia

    en.wikipedia.org/wiki/Superconducting_magnetic...

    By defining the power we can calculate the work that is needed to create such an electric field. Due to energy conservation this amount of work also has to be equal to the energy stored in the field. = / This formula can be rewritten in the easier to measure variable of electric current by the substitution.