Armature resistance of a d.c. machine is about

Related MCQs

• 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.
• 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?
• 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?
• A 220V series motor takes a current of 35A and runs at 500rpm. Armature resistance of 0.25Ω and series field resistance 0.3Ω. If iron and frictional losses amount of 600W, what is the armature torque?
• 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 speed of the motor___.
• 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.
• 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 _____.
• A 8 pole dc generator has a lap wound armature having 400 armature turns. If flux/pole is 10mWb and emf generated in armature is 200v then speed is -----rpm
• A 4 pole 1200 rpm, dc generator has lap wound armature producing 240v emf in the armature with flux/pole as 0.02Wb,then total number of armature conductors are
• A 4 pole , lap wound D.C. shunt generator has an armature winding consisting of 220 turns each of 0.004Ω. The armature resistance is ___