# Loss factor for solid bonding

This is the loss factor for sheath and screen bonded at both ends caused by circulating currents.

For GIL, $R_e$ in the following equations is replaced with the electrical resistance $R_{encl}$ of the enclosure.

Symbol
$\lambda_{1cb}$
Formulae
 $\frac{R_{e}}{R_{c} \left(\frac{R_{e}^{2}}{X_{s}^{2}} + 1\right)}$ one or two single-core and three single-core in trefoil $\frac{R_{e}}{R_{c} \left(\frac{R_{e}^{2}}{X_{s}^{2}} + 1\right)}$ three single-core in flat formation, with regular transposition $\frac{R_{e} \left(- \xi_{cb 1} + \xi_{cb 2} + \xi_{cb 3}\right)}{R_{c}}$ flat formation, not transposed, other outer phase (leading 3/T/W) $\frac{4 R_{e} \xi_{cb 2}}{R_{c}}$ flat formation, not transposed, middle phase (1/R/U) $\frac{R_{e} \left(\xi_{cb 1} + \xi_{cb 2} + \xi_{cb 3}\right)}{R_{c}}$ flat formation, not transposed, outer phase with greater loss (lagging 2/S/V) $0$ multi-core with common screen and/or common sheath $\frac{R_{sc}}{R_{c} \left(\frac{R_{sc}^{2}}{X_{s}^{2}} + 1\right)}$ multi-core with separate screen and common sheath or no sheath) $\frac{1.5 R_{e}}{R_{c} \left(\frac{R_{e}^{2}}{X_{s}^{2}} + 1\right)}$ multi-core with separate sheaths, armoured $\frac{1.0 R_{e}}{R_{c} \left(\frac{R_{e}^{2}}{X_{s}^{2}} + 1\right)}$ multi-core with separate tape screen and/or separate sheaths, unarmoured (pipe-type) $\frac{1.0 R_{e}}{R_{c} \left(\frac{R_{e}^{2}}{X_{s}^{2}} + 1\right)}$ multi-core with separate tape screen, without sheath, with non-magnetic armour (pipe-type)
Related
$R_{c}$
$R_{sc}$
Used in
$f_{SHF}$