
Electric Motors 17
Figure 1.10 Influence on flux paths when air-gap surface is slotted to
accommodate conductors
the flux, but almost all the force now acts on the rotor teeth,
rather than on the conductors.
This is very good news indeed. By putting the conductors
in slots, we simultaneously reduce the reluctance of the
magnetic circuit, and transfer the force to the rotor iron,
which is robust and well able to transmit the resulting
torque to the shaft. There are some snags, however. To
maximize the torque, we will want as much current as poss-
ible in the rotor conductors. Naturally we will work the
copper at the highest practicable curren ...