Chapter: Electrical machines : Synchronous Generator
Relation between speed and frequency
Relation between speed and
frequency
One
complete revolution will produce one complete positive and negative pulse each
cycle when the number of pole is two. The frequency in cycles per second (Hz)
will depend directly on the speed or number of revolutions per second (rpm/60)
of the rotating field.
If the ac
synchronous generator has multiple poles (having, say, two, four, six, or eight
poles...), then for a speed of one revolution per second (1 rpm/60), the
frequency per revolution will be one, two, three, or four ..., cycles per
revolution, respectively. The frequency per revolution, is therefore, equal to
the number of pairs of poles. Since the frequency depends directly on the speed
(rpm/60) and also on the number of pairs of poles (P/2), then these two may be
combined together into a single equation in which
Where
P is the number of poles
N is the speed in rpm (rev/min)
f is. the frequency in hertz
ωm is the speed in radians per second (rad/s)
ωe is the speed electrical radians per second.
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