A motor draws electric power $P_{\text {elec }}$ from a supply line and delivers mechanical power $P_{\text {mech }}$ to a pump through a rotating copper shaft of thermal conductivity $k_{s}$, length $L$, and diameter $D$. The motor is mounted on a square pad of width $W$, thickness $t$, and thermal conductivity $k_{p}$. The surface of the housing exposed to ambient air at $T_{\infty}$ is of area $A_{h}$, and the corresponding convection coefficient is $h_{h}$. Opposite ends of the shaft are at temperatures of $T_{h}$ and $T_{\infty}$, and heat transfer from the shaft to the ambient air is characterized by the convection coefficient $h_{s}$. The base of the pad is at $T_{\infty}$.