Trivia Questions On Electrical Machines

20 Questions | By Soujanya | Last updated: Mar 18, 2022 | Total Attempts: 1120

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Trivia Questions On Electrical Machines - Quiz

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1.

The inductive reactance of a transformer depends on
- A.
  
  Magnetomotive force
- B.
  
  Electromotive force
- C.
  
  Magnetic flux
2.

The inductive reactance of a transformer depends on
- A.
  
  Magnetomotive force
- B.
  
  Electromotive force
- C.
  
  Magnetic flux
3.

The emf induced in the primary
- A.
  
  Is in phase with the flux
- B.
  
  Lags behind the flux by 90degrees
- C.
  
  Leads the flux by 90degrees
4.

The flux in transformer core
- A.
  
  Increases with load
- B.
  
  Decerase with load
- C.
  
  Remain constant irrespective of load
5.

The primary ampereturns are counter balanced by
- A.
  
  Secondary ampere turns
- B.
  
  Primary flux
- C.
  
  Increase in mutual flux
6.

Power transformed from primary to secondary depends upon
- A.
  
  Number of primary turns
- B.
  
  Number of secondary turns
- C.
  
  Magnetic coupling between primary and secondary windings
7.

A transformer is supplying pure resistive load.The power factor on primary side will be
- A.
  
  About 0.95(lead)
- B.
  
  About 0.95(lag)
- C.
  
  Zero
- D.
  
  Unity
8.

The voltage regulation of a well designed transformer is of the order of
- A.
  
  20 precentage
- B.
  
  10 percentage
- C.
  
  2 percentage
- D.
  
  Zero
9.

The various losses occuring in a power transformer are------ losses
- A.
  
  Copper and iron
- B.
  
  Friction and winding
- C.
  
  Iron,friction and windage losses
10.

In the transformer circuit mode,the core loss represented as a
- A.
  
  Series resistance
- B.
  
  Series inductance
- C.
  
  Shunt resistance
- D.
  
  Shunt inductance
11.

Smooth cylindrical rotors are usually designed for
- A.
  
  2 or 4 poles
- B.
  
  8 poles
- C.
  
  12 poles
- D.
  
  24 poles
12.

A coil consists of
- A.
  
  Two coil-sides
- B.
  
  Two conductors
- C.
  
  Two turns
- D.
  
  One turn
13.

The stator of modern alternators are wound for --------- phase groups
- A.
  
  180 degrees
- B.
  
  120 degrees
- C.
  
  60 degrees
- D.
  
  240 degrees
14.

Distributed winding is preferred over concentrated winding as it
- A.
  
  Reduces noise
- B.
  
  Reduces the machine size
- C.
  
  Reduces the amount of copper required
- D.
  
  Improves the generated emf wave-form and adds rigidity and mechanical strength to wdg
15.

The doubly exicted magnetic systems are
- A.
  
  Solenoids
- B.
  
  Synchronous motors
- C.
  
  Eletromagnetic relays
16.

The cooling medium used in large sized synchrounous machines is usually
- A.
  
  Hydrogen
- B.
  
  Air
- C.
  
  Water
- D.
  
  Mineral oil
- E.
  
  Sulphur hexafluoride
17.

A polyphase field is
- A.
  
  Pulsating and stationary
- B.
  
  Pulsating and rotating
- C.
  
  Constant in amplitude and roatating at synchronous speed
- D.
  
  Constant in amplitude and sationary in space
18.

An alternator with higer value of SCR has.
- A.
  
  Poor voltage regulation and lower stability limit
- B.
  
  Better voltage regulation and higher stability limit
- C.
  
  Poor voltage regulation and higher stability limit
- D.
  
  Better voltage regulation and low stability limit
19.

The minimum no of windings required for producing a polyphase field is
- A.
  
  One
- B.
  
  Two
- C.
  
  Three
- D.
  
  None of these
20.

Number of slip-rings in a 3-phase synchronous motor will be
- A.
  
  0
- B.
  
  1
- C.
  
  2
- D.
  
  3 or 4