Electrical and Electronics Engineering MCQs | Page - 19

Q. 181) A 4 pole, 250V series motor has a wave connected armature with 1254 conductors. The flux per pole is 22mWb when the motor taking 50A. Iron and friction lossses amount to 1000W. Armature resistance 0.2Ω, series field resistance 0.2Ω. What is the output power in H.P.

Q. 182) Which motor should not be used for centrifugal pumps?

Q. 183) If the applied voltage to a DC machine is 230V, then back emf for maximum power developed is ___.

Q. 184) A DC motor runs at 1725rpm at full load and 1775rpm at no load. The speed regulation is _____.

Q. 185) A 4 pole, 500V shunt motor has 720 wave connected conductors on its armature. The full load armature current is 60A and flux per pole is 0.03Wb. The armature resistance is 0.2Ω and contact drop per brush is 1V. What is the back emf?

Q. 186) A 4 pole, 500V shunt motor has 720 wave connected conductors on its armature. The full load armature current is 60A and flux per pole is 0.03Wb. The armature resistance is 0.2Ω and contact drop per brush is 1V. What is the full load speed of the motor?

Q. 187) The armature of a 4 pole shunt motor has a lap winding accomodated in 60 slots, each containing 20 conductors, if the useful flux per pole is 23mWb, the armature torque developed when the armature current is 50A is _____.

Q. 188) The resistance of the shunt field winding as compared to series field winding is ____.

Q. 189) The field winding of a machine designed for separate excitation is

Q. 190) A shunt motor runs at 500rpm on a 200V circuit. Its armature resistance is 0.5Ω and the current taken is 30A in addition to field current. What resistance must be placed in series with armature circuit to reduce to speed to 300 rpm; the current in armature remains same.