EEL+3211+Fall+2011+HW6

EEL+3211+Fall+2011+HW6 - assuming 0.75 PF leading. b....

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EEL 3211 Fall 2011 HW#6 1. A 480V, wye connected, 60 Hz Synchronous generator with X s =0.05Ω and R A =0.02Ω is connected to the following loads. a. 1000 A, 0.6PF leading b. 1000A, 1.0PF c. 1000A, 0.6PF lagging Determine E A , the field current and sketch the phasor diagram for each if the generator is to maintain 480V at the terminals and the open circuit characteristics are provided in figure 5-24 a. What would the output voltage be for each if the loads were disconnected and the field currents stayed the same? How much power would need to be input to the generator in each case if the generator had 12 kW of friction and windage losses and 10 kW of core loss? 2. Repeat the previous problem if the generator were delta connected instead. 3. A 208 V, delta connected, 60 Hz synchronous motor with friction and windage losses of 1.2 kW and core losses of 0.9 kW has X s =2Ω and R A =0Ω. a. Determine I A , E A and the angle δ for the motor when the motor is outputting 20 hp
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Unformatted text preview: assuming 0.75 PF leading. b. Determine I A , E A and the angle for the motor when the motor is outputting 20 hp assuming 1 PF. c. Determine I A , E A and the angle for the motor when the motor is outputting 20 hp assuming 0.75 PF lagging. d. Sketch the phasor diagrams for parts a, b and c. 4. Assuming that the motor is initially operating as indicated in problem 3a above. a. Determine I A , I L and the power factor if the load on the motor changes such that the motor is now outputting 35 hp. b. Sketch the phasor diagram for the operating conditions of part a. 5. The motor of problem 3 is connected in parallel with a 10 kW 0.8 PF lagging load. a. Determine I A , E A and the angle for the motor when the motor is outputting 20 hp if the combined load is to have a 1.0 PF b. Sketch the phasor diagram for the applied voltage, the total current and the currents through the two loads...
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