Each pattern contains a sequence of stator phase firing pulses
over an electrical cycle of the drive. Each pulse of a
particular pattern is preferable of equal duration and has a
turn-on angle
corresponding to a different initial rotor position.
Therefore, MacMinn teaches varying the turn-on angle and
thereby fails to
teach enabling the switching means at a fixed angle prior to
alignment of a rotor pole with the energized stator pole and
disabling the switching means at a fixed angle after alignment
of the rotor pole with the energized stator pole as recited by
Appellants' claims.
Stephens is an improvement of the prior art disclosed by
Figure 1. However, Stephens improves the current regulation
means 51, not the control means 50. Stephens teaches in
column 5, lines 3-9, that it has been found that by regulating
current in order to produce phase current waveforms during
generating actions that are approximately mirror images, about
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Last modified: November 3, 2007