Download Homework 4 ECE 207 – Electrical Engineering Due: 9/27/2012 A

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Solar micro-inverter wikipedia, lookup

Pulse-width modulation wikipedia, lookup

Standby power wikipedia, lookup

Decibel wikipedia, lookup

Brushless DC electric motor wikipedia, lookup

Rectifier 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

Metadyne 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

AC motor wikipedia, lookup

Variable-frequency drive wikipedia, lookup

Induction motor wikipedia, lookup

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
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:
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:
Voltage (V)
Current (A)
Power (W)
No-Load Test
Blocked-Rotor Test
DC Test
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