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Temperature of armour

The temperature of armour is the mean value of the temperatures of the first and second armour layer. Because the resistances of the armour layers are calculated based on the temperatures of the corresponding layers, this temperature is not used.

With crossing heat sources, a temperature rise of $\Delta\theta_{0x}$ applies at the hottest point.

Symbol
$\theta_{ar}$
Unit
°C
Formulae
$\theta_c-T_1 \left(W_c+\frac{W_d}{2}\right)+n_{ph} T_2 \left(W_c \left(1+\lambda_1\right)+W_d\right)$
Related
$\Delta \theta_{0x}$
Temperature rise by crossing heat sources [K]
$\lambda_1$
Loss factor of shield (screen and sheath)
$n_{ph}$
Number of phases in a cable
$T_1$
Thermal resistance between one conductor and sheath [K.m/W]
$T_2$
Thermal resistance of armour bedding [K.m/W]
$\theta_c$
Temperature of conductor [°C]
$W_c$
Conductor losses [W/m]
$W_d$
Dielectric losses [W/m]
Used in
$R_{ar}$
Electrical resistance of armour [$\Omega$/m]