Electrical Machines An electric motor with constant output power will have a torque speed characteristics in the form of a Circle about the origin. Straight line through the origin. Rectangular hyperbola Straight line parallel to the speed axis. Circle about the origin. Straight line through the origin. Rectangular hyperbola Straight line parallel to the speed axis. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When the mechanical power is developed by a DC motor maximum None of above. Back emf is equal to half of applied voltage. Back emf is equal. back emf is equal to applied voltage. None of above. Back emf is equal to half of applied voltage. Back emf is equal. back emf is equal to applied voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The magnetic field which initially induces emf in the armature in a self excited DC generator is because of residual magnetism. None of these permanent magnets. armature reaction. residual magnetism. None of these permanent magnets. armature reaction. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Voltage regulation can be determined by which of the following? ZPF method. MMf method. Synchronous impedance method. All of these ZPF method. MMf method. Synchronous impedance method. All of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the efficiency when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 72.5% 82.5% 78.5% 67.5% 72.5% 82.5% 78.5% 67.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the mechanical power developed by a DC series motor is maximum? Back emf is equal to applied voltage. Back emf is equal to zero. None of above. Back emf is equal to half the applied voltage. Back emf is equal to applied voltage. Back emf is equal to zero. None of above. Back emf is equal to half the applied voltage. ANSWER DOWNLOAD EXAMIANS APP
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