Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the field winding must be replaced field winding must be excited by low voltage dc supply the field winding connection must be reversed the armature connection must be reversed the field winding must be replaced field winding must be excited by low voltage dc supply the field winding connection must be reversed the armature connection must be reversed ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If starter is not used with large DC motor for starting, it will damage the armature and commutator. draw a starting current many times its rated full load current. provide execessive voltage drop in line. all of above. damage the armature and commutator. draw a starting current many times its rated full load current. provide execessive voltage drop in line. all of above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Magnetic field of a DC generator is produced by what? Electromagnets. None of the options. Both B and C. Permanent magnets. Electromagnets. None of the options. Both B and C. Permanent magnets. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the frequency of a alternator, if P = number of poles and N = revolution made per second? 120N / P Hz. 120 / PN Hz. 120P / N Hz. PN / 2 Hz. 120N / P Hz. 120 / PN Hz. 120P / N Hz. PN / 2 Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Maximum allowable acidity level of power transformer insulating oil is generally taken as 0.5 mg of KOH / gm. 1 mg of KOH / gm. 0.3 mg of KOH / gm. 2 mg of KOH / gm. 0.5 mg of KOH / gm. 1 mg of KOH / gm. 0.3 mg of KOH / gm. 2 mg of KOH / gm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 3 - Φ, 4 pole, 50 Hz induction motor 4 % slip, calculate frequency of the rotor emf? 10 Hz. 50 Hz. 2 Hz. 3 Hz. 10 Hz. 50 Hz. 2 Hz. 3 Hz. ANSWER DOWNLOAD EXAMIANS APP
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