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  2. Neher–McGrath method - Wikipedia

    en.wikipedia.org/wiki/Neher–McGrath_method

    By estimating the temperature of the cables, the safe long-term current-carrying capacity of the cables can be calculated. J. H. Neher and M. H. McGrath were two electrical engineers who wrote a paper in 1957 about how to calculate the capacity of current (ampacity) of cables. [1]

  3. Dynamic line rating for electric utilities - Wikipedia

    en.wikipedia.org/wiki/Dynamic_line_rating_for...

    They are based on "steady-state (equilibrium) ampacity" calculations. Emergency ratings are based on transient equations and models: they provide permissible overload ratings for a short and adjustable time (typically 5 to 30 minutes). Forecasting methods have been developed to determine intraday and day-ahead ampacity forecasts.

  4. Ampacity - Wikipedia

    en.wikipedia.org/wiki/Ampacity

    The ampacity of a conductor depends on its ability to dissipate heat without damage to the conductor or its insulation. This is a function of the insulation temperature rating, the electrical resistance of the conductor material, the ambient temperature, and the ability of the insulated conductor to dissipate heat to the surroundings.

  5. Thermodynamic diagrams - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_diagrams

    The path or series of states through which a system passes from an initial equilibrium state to a final equilibrium state [1] and can be viewed graphically on a pressure-volume (P-V), pressure-temperature (P-T), and temperature-entropy (T-s) diagrams. [2] There are an infinite number of possible paths from an initial point to an end point in a ...

  6. Electrical resistivity and conductivity - Wikipedia

    en.wikipedia.org/wiki/Electrical_resistivity_and...

    The effective temperature coefficient varies with temperature and purity level of the material. The 20 °C value is only an approximation when used at other temperatures. For example, the coefficient becomes lower at higher temperatures for copper, and the value 0.00427 is commonly specified at 0 °C .

  7. Heisler chart - Wikipedia

    en.wikipedia.org/wiki/Heisler_Chart

    These first Heisler–Gröber charts were based upon the first term of the exact Fourier series solution for an infinite plane wall: (,) = = [⁡ + ⁡ ⁡], [1]where T i is the initial uniform temperature of the slab, T ∞ is the constant environmental temperature imposed at the boundary, x is the location in the plane wall, λ is the root of λ * tan λ = Bi, and α is thermal diffusivity.

  8. List of thermal conductivities - Wikipedia

    en.wikipedia.org/wiki/List_of_thermal_conductivities

    The cited Andersland Charts include corresponding water content percentages for easy measurements. The TPRC Data Book has been quoting de Vries with values of 0.0251 and 0.0109 W⋅cm −3 ⋅Kelvin −1 for the thermal conductivities of organic and dry mineral soils respectively but the original article is free at the website of their cited ...

  9. Thermal conductance and resistance - Wikipedia

    en.wikipedia.org/wiki/Thermal_conductance_and...

    is the temperature gradient (K·m −1) across the sample, A {\displaystyle A} is the cross-sectional area (m 2 ) perpendicular to the path of heat flow through the sample, Δ T {\displaystyle \Delta T} is the temperature difference ( K ) across the sample,