The armature of D.C. generator is laminated to

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

The armature of D.C. generator is laminated to

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