Satisfactory commutation of DC machines requires? Mark as favorite Copy Link brushes should be of proper grade and size brushes should smoothly run in the holders smooth, concentric commutator properly undercut all of the above Check Answer
If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be? Mark as favorite Copy Link zero small the same as rated voltage high Check Answer
In a D.C. generator? Mark as favorite Copy Link external resistance = internal characteristic - armature reaction internal characteristic = magnetisation characteristic - ohmic drop external characteristic = magnetisation characteristic - ohmic drop - armature reaction magnetisation characteristic = external characteristic Check Answer
In a D.C. generator the ripples in the direct e.m.f. generated are reduced by? Mark as favorite Copy Link using conductor of annealed copper using commutator with large number of segments using carbon brushes of superior quality using equiliser rings Check Answer
The purpose of providing dummy coils in a generator is? Mark as favorite Copy Link to reduce eddy current losses to enhance flux density to amplify voltage to provide mechanical balance for the rotor Check Answer
A D.C. generator works on the principle of? Mark as favorite Copy Link Lens's law Ohm's law Faraday's law of electromagnetic induction none of the above Check Answer
In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when? Mark as favorite Copy Link there is no load on the generator the generator runs on full load the generator runs on overload the generator runs on designed speed Check Answer
In a D.C. generator the critical resistance can be increased by? Mark as favorite Copy Link increasing is field resistance decreasing its field resistance increasing its speed decreasing its speed Check Answer
The demagnetising component of armature reaction in a D.C. generator? Mark as favorite Copy Link reduces generator e.m.f. increases armature speed reduces inter poles flux density results in sparking trouble Check Answer
In a D.C. generator the critical resistance refers to the resistance of? Mark as favorite Copy Link brushes field armature load Check Answer