Q1A 4-poles, wave wound, 600 conductors DC long shunt generatorhas the armature, series and shunt resistances are 0.15 ohm, 0.18ohm and 200 ohm respectively. It runs at 1500 rpm. Calculate thefollowing if it is required supply to the load resistance of 20ohmwith flux per pole as 8.33 mWb. Take the Iron and Frictional lossesas 550 W.(i)Induced Emf(ii)Terminal Voltage(iii)OutputPower(iv)Input Power(v)Efficiency
Q2Write short notes on following characteristics of dcgenerator(i) Open Circuit Characteristics (OCC)(ii) LoadCharacteristics
Q3A dc short shunt generator supply 500V to a 20 kW load. Itsarmature, series and shunt resistance are 0.8 ï—, 0.6 ï—and 700ï—respectively. Calculate the armature current, induced emf, inputpower, torque supplied by the prime mover and efficiency if itsspeed and mechanical losses are 1500 rpm and 910W respectively.
Q4A 500V, 4 poles, wave-wound DC Series Motor has 900 conductorson its armature. It has armature and series field resistance of0.6ï—, and 0.8ï—respectively. The motor takes a current of 40A.Estimate the speed and gross Torque developed if it has a flux perpole of 20mWb.
Q5A dc shunt motor takes a no load current of 5 A at 300V. Itsarmature and shunt resistances are 0.45 ohm and 0.68 ohmrespectively. Calculate the Constant Loss (Iron and FrictionalLoss) of the machine.
Q6A dc series motor operates at 1000 rpm with a line current of82A from 250V mains. its armature circuit resistance is 0.2ï—and itsfield resistance is 0.6ï—. Find the speed at which the motor runs ata line current of 65A, assuming that the flux at this current is33% of the flux at 82A.
Q7A 3 phase, 50Hz, 4 poles induction motor runs at 1440 rpm.Calculate the following i.Synchronous speedii.Slipiii.Slipspeediv.Rotor frequency while runningv.Rotor cu loss if mechanicalpower developed is 16 kW.
Q8A 40 kW (Rated Output), 415V, 50Hz, 3 phase, star connectedinduction motor has a synchronous speed of 1800 rpm. The full loadslip is 4% and full load power factor is 0.9 lagging. Stator Culosses are 2500 W. Iron losses are 2000W. Rotational losses are1400 W. Calculate i.Shaft or Net Torque developedii.Mechanicalpower developediii.Power inputiv.Efficiencyv.Supply current
Q9The following are the equivalent circuit parameters of a3phase, star connected 415V, 50Hz, 4 poles Induction Motor:R1=0.5ï—, R'2= 0.4/s ï—, X1= 0.9ï—, X'2= 0.8ï—, Xm= 50ï—,(neglectRo)Calculate the input impedance, motor current, power input, powersupplied to the rotor, power developed and efficiency if itsrotational losses are 1200W. It runs at 1410 rpm.
Q10A 415-V, 29.84 kW, 50 Hz, delta-connected 3-phase inductionmotor gave the following test data:No load test:415V, 15A, 2000WLocked rotor test:125V, 40A, 4000 WConstruct the circle diagramand determine the line current and power factor for the ratedoutput. Assume stator and rotor Cu losses equal at standstill.Q11With a aid of neat circuit diagram, explain the workingprinciple of Automatic star-delta starter of three phase inductionmotor
