PASCO SE-8658A PERMANENT MAGNET MOTOR User Manual

Page 32

Permanent Magnet Motor

012-07210

6. Opposite

7. Yes

8. a) The armature’s north pole alternates from end to end as the AC waveform alternates from posi-

tive to negative.

b) The slip-ring commutator connects the armature to the power source by way of the brushes and

enables the current to travel in an unbroken stream from the positive to the negative terminals of
the power supply.

Part B

3. a) The armature vibrates or pulses.

b) This happens because the alternating current causes the polarity of the armature to reverse with

each AC cycle.

4. a) It vibrates or pulses at the same frequency, but with less force.

b) This happens because the rate at which the polarity reverses is the same, but the force of the in-

duced magnetic flux of the armature decreases with decreasing voltage.

5. a) The rate of vibration is lessened, and the strength of the pulsation is increased.

b) The halving of the cycle rate of the AC results in halving the rate of reversal of polarity in the

armature, while the increase in voltage results in the increase in strength of the pulsations.

9. The rotational speed of the armature does not change when you change the voltage.

10.The speed varies directly with the AC frequency.