16.For constant torque drive which speed control method is preferred ?

17.The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator ?

18.The hysteresis loss in a D.C. machine least depends on

19.Which motor should not be started on no-load ?

20.If the terminals of armature of D.C. motor are interchanged, this action will offer following kind of braking (o) regenerative