Electrical Machines A Shunt generator running at 1000 rpm has generated emf of 100 V. If the speed increases to 1200 rpm, the generated emf will be nearly 175 V 120 V 140 V 240 V 175 V 120 V 140 V 240 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following factors improve commutation in a dc machine ? 1. High contact resistance of brushes 2. High inductance of the coils undergoing commutation 3. Shifting of brushes in the direction of rotation for a generator and in the opposite direction For a motor 4. Narrow width for the commutation bars Select the correct answer using the codes given below : Codes : 1, 2, and 3 1 and 3 1, 2 and 4 2, 3 and 4 1, 2, and 3 1 and 3 1, 2 and 4 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Hunting phenomenon is observed in which motor? Both A and C. Induction motor. Synchronous motor. DC motor. Both A and C. Induction motor. Synchronous motor. DC motor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a single phase capacitor start induction motor which of the following is valid? Direction of rotation cannot be changed. None of these. Rotation can be changed by reversing main winding terminals. Rotation can be changed by interchanging supply terminals. Direction of rotation cannot be changed. None of these. Rotation can be changed by reversing main winding terminals. Rotation can be changed by interchanging supply terminals. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The external resistance to be added in the armature circuit to limit the armature current to 125% of its rated value is 31.1 Ω 15.9 Ω 31.9 Ω 15.1 Ω 31.1 Ω 15.9 Ω 31.9 Ω 15.1 Ω ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Normally for the design of transformer the ambient temperature is taken as 27°C. 32°C. 35°C. 45°C. 27°C. 32°C. 35°C. 45°C. ANSWER DOWNLOAD EXAMIANS APP
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