Electrical Machines
Consider the following statements about commutating poles which are fitted on most large dc Shunt motors: 1. The commutating poles are placed in the geometric neutral plane and their number is usually Equal to the number of main poles 2. The winding on the commutating poles is connected in series with the shunt-field winding on the main poles 3. The polarity of the commutating pole must be that of the next pole further ahead 4. The commutating poles neutralize the reactance voltage produced in the coil undergoing Commutation. Of these statements,

 1, 2 and 4 are correct
 1, 2 and 3 are correct
 1 and 4 are correct
 2, 3 and 4 are correct

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
In a step down transformer which one of the following statements is true?

 Secondary current is less than primary current.
 Number of secondary turns is more than that of primary.
 Secondary power is less than primary power.
  Number of secondary turns is less than primary turns.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Due to magnetic saturation, the flux per pole in a DC machine without brush shift

  decreases in both generators and the motors with load.
 decreases in generators and increases in motor with load.
 increases in generators but decreases in motor with load.
 increases in both the generators and the motors with load.

ANSWER DOWNLOAD EXAMIANS APP