In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made____________?

Related Mcqs:

__________ has a low relative permeability and is used principally in field frames when cost is of primary importance and extra weight is not objectionable?

A. Cast steel B. Aluminium C. Soft steel D. Cast iron...

Hydrogen has a heat transfer co-efficient __________ times that of air?

A. 1.5 B. 2.5 C. 3.5 D. 4.5...

Which of the following methods is most accurate ?

A. Equivalent current method B. Equivalent power method C. Equivalent torque method D. Method of average losses...

Which of the following methods may be adopted to reduce the effects of armature reaction ?

A. Increase in length of air gap at pole tips B. Increasing reluctance of pole tips C. Compensating windings D. Interpoles E. All of the above...

A practical formula for determining the thickness of insulation between low voltage and high voltage windings is__________________?

A. 1 + 0.2 kVmm B. 2 + 0.5 kVmm C. 4 + 0.7 kV mm D. 5 + 0.9 kV mm...