DC MOTORS QUIZ

They reduce armature reaction

They reduce sparking

They have longer life

They have lower resistance

None of these

Mutually induced e.m.f.

Self-induced e.m.f.

Back e.m.f.

Cumulatively compounded

Differentially compounded

Level compounded

Under compounded

Armature resistance × applied voltage

Armature resistance × armature current

Flux per pole × armature current

None of the listed here

Motor will come to stop

This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses

This will make armature to take heavy current, possibly burning it

Nothing will happen to motor

To reduce the reluctance of the magnetic path

To spread out flux for better uniformity

To support the field coils

To reduce eddy current loss

On yoke in the pole faces

None of the listed here

On armature

On yoke in the interpolar gap

Normal speed

More than the normal speed

Loss than the normal speed

Zero

All of these

Low efficiency at high loads

High maintenance cost

High initial cost

Burn due to heat produced in the field winding by eddy currents

Run at normal speed

Not run

Run at lower speed