Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Homework 4 ECE 207 – Electrical Engineering Due: 9/27/2012 A
Document related concepts
Solar micro-inverter wikipedia , lookup
Pulse-width modulation wikipedia , lookup
Standby power wikipedia , lookup
Brushless DC electric motor wikipedia , lookup
Wireless power transfer wikipedia , lookup
Power inverter wikipedia , lookup
Power over Ethernet wikipedia , lookup
History of electric power transmission wikipedia , lookup
Audio power wikipedia , lookup
Buck converter wikipedia , lookup
Power factor wikipedia , lookup
Electric motor wikipedia , lookup
Electric power system wikipedia , lookup
Voltage optimisation wikipedia , lookup
Power electronics wikipedia , lookup
Amtrak's 25 Hz traction power system wikipedia , lookup
Mains electricity wikipedia , lookup
Brushed DC electric motor wikipedia , lookup
Electric machine wikipedia , lookup
Switched-mode power supply wikipedia , lookup
Three-phase electric power wikipedia , lookup
Stepper motor wikipedia , lookup
Electrification wikipedia , lookup
Alternating current wikipedia , lookup
Power engineering wikipedia , lookup
Transcript
Homework 4 ECE 207 – Electrical Engineering Due: 9/27/2012 1. A three-phase, 10 hp, 208 V, 50 Hz, 4 pole, Y-connected induction motor delivers rated output power at a slip of 2%. Determine: a. Synchronous speed b. Rotor speed c. Synchronous speed and rotor speed, if the motor had 2 poles 2. A three-phase, 25 hp, 230 V, 60 Hz induction motor draws 60 A from the source at 0.866 lagging power factor. The motor losses are: Stator copper loss, Pcu1 = 850 W Magnetic core loss, Pcore = 450 W Rotor copper loss, Pcu2 = 1050 W Rotational loss, Prot = 500 W Find: a. b. c. d. e. Air gap power, Pag Slip, s Mechanical power developed, Pdev Output power, Pout Efficiency of the motor, η 3. A three-phase, 50 hp, 460 V, 60 Hz, 4 pole, induction motor has the following data: R1 = 0.1 Ω X1 = 0.35 Ω R2 = 0.125 Ω X2 = 0.40 Ω Rc = 1200 Ω Xm = 100 Ω This motor operates at a slip of 2.5%. Ignoring windage losses, calculate: a. b. c. d. e. f. Line current, I1 Input power, Pin Input power factor, pf Efficiency, η Starting current, Istart Starting power factor, pfstart 4. A three-phase, 5 hp, 208 V, 4 pole, 60 Hz induction motor is subjected to no-load, blockedrotor, and DC tests. The following data was collected from these tests: Variable Voltage (V) Current (A) Power (W) No-Load Test 208 4 250 Blocked-Rotor Test 35 12 450 DC Test 20 25 Find: a. Parameters of the equivalent circuit b. Draw the equivalent circuit with parameter values specified on it 5. For the motor of Problem 4, it is desirable to improve the power factor to 0.98 lagging. If the slip is 5% and terminal voltage is 208 V, then calculate: a. Reactive power of the capacitor/phase for power factor correction b. Capacitance of the Y-connected capacitor/phase for power factor correction
