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  2. Per-unit system - Wikipedia

    en.wikipedia.org/wiki/Per-unit_system

    The main idea of a per unit system is to absorb large differences in absolute values into base relationships. Thus, representations of elements in the system with per unit values become more uniform. A per-unit system provides units for power, voltage, current, impedance, and admittance. With the exception of impedance and admittance, any two ...

  3. Skin effect - Wikipedia

    en.wikipedia.org/wiki/Skin_effect

    The internal impedance per unit length of a segment of round wire is given by: [6]: 40 = (). This impedance is a complex quantity corresponding to a resistance (real) in series with the reactance (imaginary) due to the wire's internal self- inductance , per unit length.

  4. Reaction rate - Wikipedia

    en.wikipedia.org/wiki/Reaction_rate

    Iron rusting has a low reaction rate. This process is slow. Wood combustion has a high reaction rate. This process is fast. The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time. [1]

  5. Reactances of synchronous machines - Wikipedia

    en.wikipedia.org/wiki/Reactances_of_synchronous...

    Technically, these constants are specified in units of the electrical reactance , although they are typically expressed in the per-unit system and thus dimensionless. Since for practically all (except for the tiniest) machines the resistance of the coils is negligibly small in comparison to the reactance, the latter can be used instead of ...

  6. Reaction rate constant - Wikipedia

    en.wikipedia.org/wiki/Reaction_rate_constant

    where A and B are reactants C is a product a, b, and c are stoichiometric coefficients,. the reaction rate is often found to have the form: = [] [] Here ⁠ ⁠ is the reaction rate constant that depends on temperature, and [A] and [B] are the molar concentrations of substances A and B in moles per unit volume of solution, assuming the reaction is taking place throughout the volume of the ...

  7. Electrical reactance - Wikipedia

    en.wikipedia.org/wiki/Electrical_reactance

    In electrical circuits, reactance is the opposition presented to alternating current by inductance and capacitance. [1] Along with resistance, it is one of two elements of impedance; however, while both elements involve transfer of electrical energy, no dissipation of electrical energy as heat occurs in reactance; instead, the reactance stores energy until a quarter-cycle later when the energy ...

  8. Electrical susceptance - Wikipedia

    en.wikipedia.org/wiki/Electrical_susceptance

    The reactance and susceptance are only reciprocals in the absence of either resistance or conductance (only if either R = 0 or G = 0, either of which implies the other, as long as Z ≠ 0, or equivalently as long as Y ≠ 0).

  9. Siemens (unit) - Wikipedia

    en.wikipedia.org/wiki/Siemens_(unit)

    The siemens (symbol: S) is the unit of electric conductance, electric susceptance, and electric admittance in the International System of Units (SI). Conductance, susceptance, and admittance are the reciprocals of resistance, reactance, and impedance respectively; hence one siemens is equal to the reciprocal of one ohm (Ω −1) and is also referred to as the mho.