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Neher–McGrath method. In electrical engineering, Neher–McGrath is a method of estimating the steady-state temperature of electrical power cables for some commonly encountered configurations. By estimating the temperature of the cables, the safe long-term current-carrying capacity of the cables can be calculated.
An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the maximum operating temperature (or peak operating ...
A hot, less-dense lower boundary layer sends plumes of hot material upwards, and cold material from the top moves downwards. Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy ( heat) between physical systems. Heat transfer is classified into various mechanisms ...
In heat transfer, thermal engineering, and thermodynamics, thermal conductance and thermal resistance are fundamental concepts that describe the ability of materials or systems to conduct heat and the opposition they offer to the heat current. The ability to manipulate these properties allows engineers to control temperature gradient, prevent ...
Thermistor. A thermistor is a semiconductor type of resistor whose resistance is strongly dependent on temperature, more so than in standard resistors. The word thermistor is a portmanteau of thermal and resistor . Thermistors are categorized based on their conduction models. Negative-temperature-coefficient (NTC) thermistors have less ...
At high temperatures, the resistance of a metal increases linearly with temperature. As the temperature of a metal is reduced, the temperature dependence of resistivity follows a power law function of temperature. Mathematically the temperature dependence of the resistivity ρ of a metal can be approximated through the Bloch–Grüneisen formula:
Dynamic line rating ( DLR ), also known as real-time thermal rating ( RTTR ), is an electric power transmission operation philosophy aiming at maximizing load, when environmental conditions allow it, without compromising safety. Research, prototyping and pilot projects were initiated in the 1990s, but the emergence of the "smart grid ...
Quantity (common name/s) (Common) symbol/s Defining equation SI units Dimension Temperature gradient: No standard symbol K m −1 [Θ][L] −1 Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer