DESIGN OF ELECTRICAL MACHINES PREPARED BY BOMMIRANI B

Which of the following circuit is designed to dissipate heat produced in the machine?

• a) Electric circuit
  

• b) Magnetic circuit
  

• c) Dielectric circuit
  

• d) Thermal circuit

How should be the magnetic and electrical loadings in a highly efficient electric machine?

• a) It must be small
  

• b) It must be large
  

• c) It must be equal to the current density
  

• d) It must be equal to the flux density

Which of the following factor mainly determines the type of insulation for an electrical machine?

• a) Maximum allowable flux density
  

• b) Maximum operating temperature
  

• c) Maximum efficiency of the machine
  

• d) Maximum allowable loss in machine

Which of the following kind of conductors will require thicker insulation?

• a) Large sized conductor
  

• b) Small-sized conductor
  

• c) Conductors with high permeance
  

• d) Conductors with low permeance

What kind of emf is produced in an electric machine when the coil is stationary and flux varies with time?

• a) Transformer emf
  

• b) Motional emf
  

• c) Interactional emf
  

• d) Induction emf

Which of the following materials is generally used in the design of electromagnetic machines?

• a) Paramagnetic materials
  

• b) Diamagnetic materials
  

• c) Ferromagnetic materials
  

• d) Core-magnetic materials

What determines the output of a dc electric machine?

• a) Only Total Magnetic loading
  

• b) Only Total Electric loading
  

• c) Total loadings
  

• d) Either Total Magnetic loading or Total Electric loading

What are the main dimensions of a rotating electric machine?

• a) Field diameter and Armature core length
  

• b) Armature diameter and Field core length
  

• c) Armature diameter and Armature core length
  

• d) Field diameter and Field core length

What kind of materials are used to design electrical heating devices?

• a) High Conductivity Materials
  

• b) High Resistivity Materials
  

• c) High Weldability Materials
  

• d) High Solderability Materials

What must be mainly ensured to keep the temperature rise within limits?

• a) Good efficiency of the machine
  

• b) Proper cooling and ventilation
  

• c) Proper saturation level
  

• d) Good insulation