
Conventional d.c. Motors 79
flux
(0).
We obviously make use of this when we want the
motor to run in reverse, and sometimes when we want re-
generative braking.
The alert reader might rightly challenge the claim made
above that the torque will be constant regardless of rotor
position. Looking at Figure 3.3, it should be clear that if the
rotor turned just a few degrees, one of the five conductors
shown as being under the pole will move out into the region
where there is no radial flux, before the next one moves under
the pole. Instead of five conductors producing force, there
will then be only four, so won't the torque be reduced
accordingly ...