# Recent questions and answers in DC generator

The terminal voltage of a DC shunt generator drops on load because of all of the following except : (A) Armature reaction (B) Armature resistance drop (C) Commutation (D) Field weakening due to armature reaction and armature resistance drop

If we have 30kva, 250 kva, 300kva d.g set than how many earthing we do?

If a self excited d.c. generator after being installed, fails to build up voltage on its first trial run, the first thing to do is (a) reverse the field winding connections (b) increase the field resistance (c) decrease the speed of prime mover (d) increase the speed of prime mover

A cumulatively compounded d.c. generator is supplying 20 A at 200 V. If the series field winding is short circuited, the terminal voltage will (a) remain unaltered (b) rise to 220 V (c) shoot up to a very high value (d) become less than 200 V

A 8-pole, DC generator has a simplex wave-wound armature containing 32 coils of 6 turns each. Its flux per pole is 0.06 Wb. The machine is running at 250 rpm. The induced armature voltage is  (A) 96 V (B) 192 V (C) 384 V (D) 768 V

The voltage built-up process of a d.c. generator is  1. difficult 2. delayed 3. cumulative 4. Infinite

for the voltage built-up a self-excited D.C. generator, which of the following is not an essential condition.  1.there must be some residual flux  2.field winding mmf must aid the residual flux  3.total field circuit resistance must be less than t critical value  4.armature speed must be very high

The slight curvature at the lower end of the O.C.C. of a self-excited dc generator is due to  1. residual pole flux 2. high armature speed 3.magnetic inertia 4. high field circuit resistance

In a DC shunt generator working on load, the brushes are moved forward in the direction of rotation, as a result of this, commutation will   (a) Improve but terminal voltage will fall   (b) Worsen and terminal voltage will fall   (c) Improve and terminal voltage will rise   (d) worsen and terminal voltage will rise

The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be?

A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly?