initial value and the 24th to 5%. The relationship between
the torque at the output of the motor and the speed is
dependant on the inertia and the viscous friction of the
mechanical systems. The higher the frequency of the torque
ripple, the lower the signal detectable on the speed data will
be. For this experiment, the motor was rotating at 7.1Hz
which means the 20th and 24th harmonics occurred at
142Hz and 170.4Hz respectively. Operating the motor as a
higher speed may mean that torque ripple for these
harmonics may not be of a sufficient magnitude to detect
and therefore cancel.