A 575 V, 60HZ, 50 hp, 873rpm, 8-pole, 3-phase, wye-connected, squirrel cage induction motor is operating under rated conditions. The motor line current is 50.75 A per phase. From previous tests, it is known that iron losses are 1.75 kW and friction-and-windage losses are 3.25 kW. The stator resistance is 0.15 2 per phase. Draw a power flow (line) diagram for the motor. Clearly label all powers on your diagram, using the appropriate symbols and values provided above. Calculate the following for this motor: a) The rotor slip: b) The mechanical power developed by the rotor (Pmech) before friction and windage losses. Pmech

A 125-hp, 480-V, 50-Hz, 6-pole, Y-connected induction motor has the per-phase equivalent circuit parameters as follows: Nominal code Locked rotor, letter kVA/hp R = 0.15 2 R2 = 0.10 2 X1 = 0.360 X2 = 0.36 2 C 3.55 – 4.00 =8.362 D 4.00 – 4.50 E 4.50 – 5.00 F 5.00 – 5.60 The core-losses are 1.7 5.60 – 6.30 kW, mechanical losses are 1.8 kW, and stray losses are 50 W. a) b) Calculate the speed at the pullout torque in rpm, the pullout torque, and the starting torque using exact Thevenin parameters. c) Find the starting code letter assigned to this motor.

Q2] Fill in the blank (9 Marks) 1-The current drwan by the armature of D.C. motor is directly proportional to 2- The speed of a D.C. shunt-wound motor will shunt field regulator is increased. 3- The synchronous speed of a three-phase induction motor is number of pairs of poles. Rotor copper losses Rotor input power in induction motor = 5- A 4-pole three-phase induction motor has a synchronous speed of 25 r.p.s. The frequency of the supply to the stator is_ Hz. 6- The power input to a mains transformer is 200VA. If the primary current is 2.5A, the secondary voltage is 2V and assuming no losses in the transformer, the turns ratio step down. is 7- A 200kVA transformer has an iron loss of 1 kW and full load cu loss of 2 kW. Its load kVA corresponding to maximum efficiency is kVA. 8- If cu loss of a transformer at 7/8th full load is 4900 W, then its full-load cu loss would be watt. 4- if the value of resistance of the proportional to the 9- The slight curvature at the lower end of the open…