DC Generator and AC Motor Quiz

In DC generator, the electricity produced at armature is

• pulsating DC

• DC

• AC

Which law states that "When a conductor moves through a magnetic field, or when the magnetic field around it changes, a voltage is induced in the conductor. If the circuit is closed, this voltage causes a current to flow"?

• Fleming's law

• Faraday's law

• Lenz's law

Which one of the characteristic refers to wave winding type?

• There are always two parallel paths irrespective of the number of poles

• The number of path depends on the number of poles

• The number of path depends on the number of brushes set

Which one is NOT the purpose of Field Frame housing or Yoke?

• Act as Protecting Shield for generator

• To produce magnetic field

• To provide mechanical support for the poles

What is reactance voltage in a DC generator caused by?

• Interaction and resultant distortion of the main field by the armature field.

• Self-inductance of the armature windings

• Commutator segments misalignment

How can the negative effects of armature reaction be reduced?

• Increasing armature resistance

• Using carbon brushes

• Adding compensating windings or interpoles

Which of the following is a characteristic of a compound wound DC generator?

• Voltage drop significantly after the saturation point, as the load increases.

• Voltage remains constant regardless of load changes.

• Voltage drop as load increases

When testing armature coils with one of test lamp's probe on the shaft and another on commutator segment, the lamp illuminates. This indicates the coil is:

• Grounded

• Short circuit

• Open circuit

In a DC alternator the magnetic field is on the ______ and the output is taken out from the ______.

• Field coil, armature

• Stator, rotor

• Rotor, stator

The output of three phase alternator is rectified from AC to DC by using a:

• Slip rings

• Diode rectifier

• Commutator