Appeal No. 1998-3072 Page 3
Application No. 08/769,610
power output against time. A current curve (1100) depicts
current flow as a square wave; a power curve (1101) represents
applied or input power. The torque produced and, as such, the
output power, falls off at the end of each cycle of input
current or power as shown in a period (1103) of curve (1101).
The reduced motor power output during the period (1103)
results from the variations in the magnetic coupling between
the rotor and stator windings, and the duration of such
periods is about twenty to thirty percent of the total power
input time represented by the current curve (1100). A power
savings is possible with little sacrifice in output
performance by switching off the input power during these low
torque-to-current periods (1103).
Figures 22B and 22C diagram the inventive circuitry for
calculating a correct turnoff signal over a wide range of
motor speeds. The turnoff signal controls energization of the
motor windings as a function of relative rotor position,
notwithstanding that the Hall sensor may indicate that
continuous power should be applied to the windings.
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 Next
Last modified: November 3, 2007