Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again field winding must be excited by low voltage dc supply the field winding must be replaced the field winding connection must be reversed the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding must be replaced the field winding connection must be reversed the armature connection must be reversed ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3-phase, alternator has generated emf per phase of 230 V with 10% 3rd harmonic and 6% 5th harmonic content. Calculate rms line voltage for star connection. 50 V. 399 V. 230.2 V. 100 V. 50 V. 399 V. 230.2 V. 100 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If residual magnetism of a shunt generator is destroyed accidentally it may be restored by connecting its shunt field in reverse. to a DC source. to an AC source. to earth. in reverse. to a DC source. to an AC source. to earth. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following machines have highest power factor with respect to magnetizing current? Closed slot type machines. Any of the above. Semi closed slot type machine. Open slot type machines. Closed slot type machines. Any of the above. Semi closed slot type machine. Open slot type machines. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The direction of rotation of a DC motor can be determined by Fleming's right hand rule. Lenz's law. Ampere's law. Fleming's left hand rule. Fleming's right hand rule. Lenz's law. Ampere's law. Fleming's left hand rule. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, 1. reactance voltage is proportional to armature current 2.reactance voltage is proportional to core length 3.reactance voltage is due to self-flux of the coil undergoing commutation 4. armature-cross flux is neutralized by interpolar flux 5. interpolarmmf is more than armature mmf in the interpolar zone From these, the correct answer is 1, 3, 5 1, 2, 3, 4 2, 3, 4 1, 2, 5 1, 3, 5 1, 2, 3, 4 2, 3, 4 1, 2, 5 ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS