電動機一問?急....12345678

50Hz 電源，6 極交流電動機（摩打），其同步轉速每分鐘是 1000 轉。
摩打理論轉速為2*60*50/6=1000，也就是每分鐘1000轉。
(2) 1 Pair of pole x time (s per m) x frequency (Hz) / pole

Frequency = 50 Hz
Period = 1/f = 1/50 = 0.02 s

As polarity of the induced voltage (e.m.f.) changes whenever the coil
has rotated to half cycle. {thus, one cycle of coil make the polarity of induced emf reverses twice}

So, speed of the rotation of coil = 1/2(0.02) = 25 revolutions / s

So, the coil rotates 25(60) times per minute,
i.e. 1500 rev / min.

* Please remind the function of slip rings in dynamo.

2009-04-19 17:28:06 補充：
Sorry, the speed of the rotation of coil should also = 50 Hz = 50 revolutions / s
So, the coil rotates 50(60) times per minute
i.e. 3000 rev / min.

In dynamo, frequency of the a.c. voltage and current is equal to the frequency of
the rotating coil

2009-04-19 17:29:24 補充：
In d.c. generator, frequency of the d.c. voltage and current is half of the frequency of the rotating coil

2009-04-19 17:32:46 補充：
polarity of the induced voltage (e.m.f.) changes whenever the coil
has rotated to one cycle. {thus, one cycle of coil make the polarity of induced emf reverses once}