Electrical Machines A delta/star transformer is connected in parallel to a star/delta transformer. The turn ratio former is x times latter, the x is √3 1/3 1/√3 3 √3 1/3 1/√3 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA 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 speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 940 RPM 920 RPM 960 RPM 970 RPM 940 RPM 920 RPM 960 RPM 970 RPM ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines At the instant of starting, the per unit slip of 3 - Φ induction motor is 0.05. 0.5. 1.0. 0.1. 0.05. 0.5. 1.0. 0.1. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In case of 3 - Φ IM, plugging means interchanging two supply phases for quick stopping. locking of rotor due to harmonics. starting the motor on load which is more than the rated load. pulling the motor directly on line without a rotor. interchanging two supply phases for quick stopping. locking of rotor due to harmonics. starting the motor on load which is more than the rated load. pulling the motor directly on line without a rotor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A bipolar dc machine with interpoles has a main-pole flux of ф per pole and an interpole flux of Фᵢ per pole. The yoke of the machine is devide into four quadrants by the main-pole axis and The commutation axis. The flux-distribution in the quadrants will be ½ ( ф + фᵢ ) in all the four quadrants ½ ( ф - фᵢ ) in all the four quadrants ½ ( ф + фᵢ ) in two diametrically opposite quadrants and ½ ( ф - фᵢ ) in the remaining two Quadrants ½ ( ф + фᵢ ) in two adjacent quadrants and ½ ( ф - фᵢ ) in the remaining two quadrants ½ ( ф + фᵢ ) in all the four quadrants ½ ( ф - фᵢ ) in all the four quadrants ½ ( ф + фᵢ ) in two diametrically opposite quadrants and ½ ( ф - фᵢ ) in the remaining two Quadrants ½ ( ф + фᵢ ) in two adjacent quadrants and ½ ( ф - фᵢ ) in the remaining two quadrants ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that Eb is unchanged, but Td is zero Eb is zero, but Td is unchanged both Eb and Td are zero both Eb and Td are unchanged Eb is unchanged, but Td is zero Eb is zero, but Td is unchanged both Eb and Td are zero both Eb and Td are unchanged ANSWER DOWNLOAD EXAMIANS APP
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