Electrical Machines If the applied voltage of a certain transformer is increased by 50% and the frequency is reduced by 50%, the maximum flux density will (assuming that the magnetic circuit remains unsaturated) changes to 0.5 times the original value changes to three times the original value changes to 1.5 times the original value remain the same as the original changes to 0.5 times the original value changes to three times the original value changes to 1.5 times the original value remain the same as the original 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%. 78.5% 72.5% 67.5% 82.5% 78.5% 72.5% 67.5% 82.5% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The direction of rotation of a DC compound motor can be reversed by interchanging armature or field connections. series field connections. shunt field connections. armature connections. armature or field connections. series field connections. shunt field connections. armature connections. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC Motor 3 point starter is used to all of above. provide protection against Low-Voltage. limit the starting current to a safer value. provide overload protection. all of above. provide protection against Low-Voltage. limit the starting current to a safer value. provide overload protection. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In escalator which motor is used? Universal motor. DC shunt motor. 1 - φ IM. 3 - φ IM. Universal motor. DC shunt motor. 1 - φ IM. 3 - φ IM. 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. 230.2 V. 399 V. 50 V. 100 V. 230.2 V. 399 V. 50 V. 100 V. ANSWER DOWNLOAD EXAMIANS APP
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