Electrical Machines
What is the frequency of a alternator, if P = number of poles and N = revolution made per second?

 120 / PN Hz.
 120P / N Hz.
  PN / 2 Hz.
 120N / P Hz.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
A bipolar dc machine with interpoles has a main-pole flux of ф per pole and an interpole flux of Фᵢ per pole. The yoke of the machine is devide into four quadrants by the main-pole axis and The commutation axis. The flux-distribution in the quadrants will be

 ½ ( ф + фᵢ ) in all the four quadrants
 ½ ( ф + фᵢ ) in two adjacent quadrants and ½ ( ф - фᵢ ) in the remaining two quadrants
 ½ ( ф + фᵢ ) in two diametrically opposite quadrants and ½ ( ф - фᵢ ) in the remaining two Quadrants
 ½ ( ф - фᵢ ) in all the four quadrants

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
In speed control of DC Series motor, speed lower than the rated speed can be obtained by

 Any of the above.
 Connecting an additional resistance in the armature circuit.
 Connecting an additional resistance in the field circuit.
 Connecting an additional resistance in stator circuit.

ANSWER DOWNLOAD EXAMIANS APP