If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be____________?
(A) zero
(B) small
(C) the same as rated voltage
(D) high
The purpose of providing dummy coils in a generator is__________________?
(A) to reduce eddy current losses
(B) to enhance flux density
(C) to amplify voltage
(D) to provide mechanical balance for the rotor
A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be_____________?
(A) zero
(B) about 2 V
(C) about 50 V
(D) 220 V
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_______________?
(A) 150 V
(B) 175 V
(C) 240 V
(D) 290 V
A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will_____________?
(A) will be zero
(B) will be of 5 Hz
(C) will be of 5 xiVHz
(D) will be of v Hz 5
The purpose of providing dummy coils in a generator is____________?
(A) to reduce eddy current losses
(B) to enhance flux density
(C) to amplify voltage
(D) to provide mechanical balance for the rotor
In D.C. generators on no-load, the air gap flux distribution in space is______________?
(A) sinusoidal
(B) triangular
(C) pulsating
(D) flat topped
The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except:_____________?
(A) armature reaction
(B) armature resistance drop
(C) field weakening due to armature reaction and armature
(D) commutation
In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralised by all of the following except______________?
(A) interpoles
(B) dummy coils
(C) compensating winding
(D) shifting of axis of brushes
The critical resistance of the D.C. generator is the resistance of_____________?
(A) field
(B) brushes
(C) armature
(D) load