Cableizer ®

Temperature sheath

The formulae to calculate the loss factor for sheath $\lambda_1$ use the resistance of the sheath $R_{sh}$ at its maximum operating temperature. Because the temperature of the sheath is a function of the current, $I_c$, an iterative method is used for the calculation.

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

Symbol
$\theta_{sh}$
Unit
°C
Formulas
$\theta_c-T_1 \left(W_c+\frac{W_d}{2}\right)$without screen
$\theta_{sc}-T_{scs} \left(W_c \left(1+\lambda_{11,sc}\right)+\frac{W_d}{2}\right)$with screen
$\theta_{sc}-n_c \left(T_{scs}+T_f\right) \left(W_c \left(1+\lambda_{11,sc}\right)+\frac{W_d}{2}\right)$multicore type with screen SC
Related
$\Delta \theta_{0x}$
Temperature rise by crossing heat sources [K]
$\lambda_{11,sc}$
Loss factor screen, circulating currents
$n_c$
Number of conductors cable
$T_1$
Thermal resistance conductor—sheath [K.m/W]
$T_f$
Thermal resistance filler [K.m/W]
$T_{scs}$
Thermal resistance screen serving [K.m/W]
$\theta_c$
Temperature conductor [°C]
$\theta_{sc}$
Temperature screen [°C]
$W_c$
Conductor losses (phase) [W/m]
$W_d$
Dielectric losses (phase) [W/m]
Used in
$R_{sh}$
Electrical resistance sheath [$\Omega$/m]
$\rho_{sh}$
Specific electrical resistivity sheath material [$\Omega$.m]
$\theta_s$
Temperature screen/sheath [°C]