Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the field winding connection must be reversed field winding must be excited by low voltage dc supply the field winding must be replaced the armature connection must be reversed the field winding connection must be reversed field winding must be excited by low voltage dc supply the field winding must be replaced 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. 230.2 V. 100 V. 399 V. 50 V. 230.2 V. 100 V. 399 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The rotor speed of an induction motor is given by Nr = 120f / p × (1-s). Ns = 120f / p × ( 1 - s ). Ns = 120f /p × ( 1 - r). None of these Nr = 120f / p × (1-s). Ns = 120f / p × ( 1 - s ). Ns = 120f /p × ( 1 - r). None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If dimension of all the parts of a synchorous generator and the number of field and armature turns are double, then generated voltage will change by a factor of 2. 1. 8. 4. 2. 1. 8. 4. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a loaded DC generator, if the brushes are given a shift from the interpolar axis in the direction of rotation, then the commutation will deteriorate with rise in terminal voltage. deteriorate with fall of terminal voltage. improve with fall of terminal voltage. improve with rise in terminal voltage. deteriorate with rise in terminal voltage. deteriorate with fall of terminal voltage. improve with fall of terminal voltage. improve with rise in terminal voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A part an alternator winding consist of eight coils in series, each having an emf of 20 V rms induced in it. Coils are placed in successive slots and between each slot and the next, there is an electrical phase displacement of 30°. Find the emf of eight coils in series 86.91 V. 66.91 V. 76.91 V. 56.91 V. 86.91 V. 66.91 V. 76.91 V. 56.91 V. ANSWER DOWNLOAD EXAMIANS APP
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