# Temperature of conductors

*The conductor temperature is an input necessary in order to calculate the conductor losses, and hence the machine efficiency.*

Since the resistivity of copper and aluminum conductors is largely temperature dependent, Emetor requires you to provide the expected conductor temperature in order to accurately estimate the conductor losses. The temperature dependency of the resistivity is: $$\rho _{T} = \rho _{20^\circ\mathrm{C}} \left[ 1+\alpha \left( T-20^\circ\mathrm{C}\right) \right],$$ where $\rho$ is the resistivity and $\alpha$ is the temperature coefficient of the resistivity.

Keep in mind that electrical machines are usually designed with an average temperature well below the maximum hot-spot temperature allowed by the chosen thermal insulation class of the winding. The actual conductor temperature will also heavily depend on operating conditions and cooling arrangement of your electrical machine. Providing an inaccurate estimation of the conductor temperature largely influences the calculation of the conductor losses and machine efficiency.

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