Electrical Machines Direction of rotation of DC motor is reversed by Interchanging armature and field connection. Reversing supply connection. Reversing armature connection or field connection. Adding resistance to field circuit. Interchanging armature and field connection. Reversing supply connection. Reversing armature connection or field connection. Adding resistance to field circuit. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, the field-flux axis and armature-mmf axis are respectively along quadrature axis and direct axis direct axis and indirect axis quadrature axis and interpolar axis direct axis and interpolar axis quadrature axis and direct axis direct axis and indirect axis quadrature axis and interpolar axis direct axis and interpolar axis ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole 50 Hz induction motor is running at 1470 rpm. Find the speed of stator magnetic field with respect to rotor? 30 rpm 1500 rpm zero 1470 rpm 30 rpm 1500 rpm zero 1470 rpm 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 4 1, 2, and 3 1 and 3 2, 3 and 4 1, 2 and 4 1, 2, and 3 1 and 3 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the source voltage of a DC motor is increased, which of the following will decrease? Starting torque, operating speed, full load current. Operating speed. Starting torque. Full load current. Starting torque, operating speed, full load current. Operating speed. Starting torque. Full load current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 500 V, 55 kVA single phase alternator has an effective resistance of 0.5 Ω. An excitation current of 10 A produces 200 A armature current on short circuit and an emf of 450 V on per circuit. The synchronous reactance will be 25.564 Ω. 2.241 Ω. 2.74 Ω. 2.781 Ω. 25.564 Ω. 2.241 Ω. 2.74 Ω. 2.781 Ω. ANSWER DOWNLOAD EXAMIANS APP
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