The commutation process involves basically reversal of current in armature coil as it crosses MNA.

If the magnetic circuit of the dc machine is in the saturation region, the armature reaction

A 400-V, 1000-A, lap wound dc machine has 10 poles, 860 armature conductors. The number of conductors in the pole face to give full compensation if pole face covers 70% of pole span is

The compensating winding in dc generator is provided to

The brushes are placed

The principle contributors to magneto motive force is/are

If the critical commutation time is 2 ms but it was observed that the practical commutation took 2.5 ms. This is the case of

The number of compensating conductors/pole faces is _______ where Z is the number of active armature conductors/pole; A is number of parallel paths;
(Ia is the armature current)

Each of the following is valid for interpoles except

The absence of compensating winding lead to

The armature reaction is produced mainly by

With no commutating poles used the brushes are given backward lead in the dc motor.

The coil under going commutation lies along _____ while the coil getting short circuited lies along ____ for a practical dc machine.

The brushes should be shifted in _______ direction in generator for the satisfactory operation of commutation

Mark the most incorrect. In dc generator, commutation can be improved by