Related Questions

Laminated cores, in electrical machines, are used to reduce
A Copper loss
B Eddy current loss
C Hysteresis loss
D All of the above
A laminated glass upon cracking
A Bursts into sharp edged fragments
B Bursts into granular pieces
C Sandwiched layer traps the fragments
D Breaks into the form of crystals
A transformer core is laminated to
A reduce hysteresis loss
B reduce eddy current losses
C reduce copper losses
D reduce all above losses
A laminated iron core has reduced eddy-current losses because
A More wire can be used with less D.C. resistance in coil
B The laminations are insulated from each other
C The magnetic flux is concentrated in the air gap of the core
D The laminations are stacked vertically
In AC. circuits, laminated iron is invariably used in order to
A Reduce eddy current loss
B Increase heat radiation
C Make assembly cheap and easier
D Reduce circuit permeability
Dermatologists tell us (P) that the skin (Q) is finely laminated coating (R) whose layered nature (S) has inspired comparisons with onions
A PQRS
B PRQS
C PRSQ
D PSRQ
The demagnetizing component of armature reaction in a D.C. generator
A Reduces generator e.m.f.
B Increases armature speed
C Reduces interpoles flux density
D Results in sparking trouble
In a separately excited generator supplying rated load the armature reaction:
A Is always present
B Is always absent
C May be sometimes present
D None of the above
For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f.?
A Lap winding
B Wave winding
C Either of (A) and (B) above
D Depends on other features of design
Armature reaction in a generator results in
A Demagnetization of leading pole tip and magnetization of trailing pole tip
B Demagnetization of trailing pole tip and magnetization of leading pole tip
C Demagnetizing the center of all poles
D Magnetizing the center of all poles

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