dougherty christopher 2002 introduction to econometrics oxford university press

... Econometrics, John Willeys & Sons Salvatore, Dominick and Reagle Derrick (2002) , Statistics and Econometrics, McGraw-Hill Dougherty, Christopher (2002) , Introduction to Econometrics, Oxford University ... Kinh tế, Tài chinh Ngân hàng Chính quy Anh C Tin B To n học Chính quy Anh C Tin B Nguyễn Thị Thuý Quỳnh Trình độ Chuyên ngành 18/6/74 Trưởng môn TS To n xác suất Phó trưởng môn TS Công nghệ thông ... Econometrics, McGraw-Hill Dougherty, Christopher (2002) , Introduction to Econometrics, Oxford University Press Chính sách môn học yêu cầu khác giảng viên - Lên lớp đầy đủ - Làm tập nghiên cứu tài liệu...

Ngày tải lên: 08/02/2017, 09:15

... 1977 Arnold C Harberger, “Toward An Operational Approach to Social Cost-Benefit Analysis”, University of Chicago, 1974, mimeo Peterie, Amalio Humberto., “Rates of Retutn to Physical Capital in Manufacturing ... Argentina”, unpublished Ph D disertation, University of Chicago, 1971 Harberger, Arnold C., and Wisecarver, Daniel L., “Private and Social Rates of Return to Capital in Uruguay”, Economic Development ... tổng thu nhập (từ doanh thu) tổng chi phí, ngân lưu ròng tính chênh lệch tổng thu (total receipts) tổng chi (total expenditures) Do đó, có số biến số phải định nghĩa rõ ràng quan hệ chúng phải...

Ngày tải lên: 27/07/2014, 11:02

... for compressed-air installations that is used both to store the compressed air and to permit pressure to be equalized in the system { er ri seи ¯ vər } air register [ENG] A device attached to an ... accelerator pedal of an automotive vehicle to the carburetor throttle valve or fuel injection control { ak selиə radиər liŋиkij } ¯ accelerator pedal [MECH ENG] A pedal that operates the carburetor ... namиəиdər } ¨ absolute pressure gage [ENG] A device that measures the pressure exerted by a fluid relative to a perfect vacuum; used to measure pressures ¨ very close to a perfect vacuum { abиsə...

Ngày tải lên: 27/06/2014, 18:20

Ngày tải lên: 13/03/2016, 20:34

... general information needs by referring to Varsity Motors, Inc., an automobile dealership Varsity Motors seeks to earn a profit by selling new and used automobiles and parts and accessories, and ... needs to know what automobiles are available for sale and each one’s cost and selling price When an automobile is sold, a record must be made of that fact The person in the stockroom needs to know ... inventory of a certain part becomes depleted, this fact needs to be known so that an additional quantity can be ordered Amounts owed by the company’s customers need to be known; and if a customer...

Ngày tải lên: 23/03/2014, 03:20

Ngày tải lên: 04/04/2014, 23:52

... 0.262 T in the top, left, and bottom legs of the core can be found from Figure P1-9 to be H top = H left = H bottom = 240 A ⋅ t/m The total MMF required to produce the flux is FTOT = H ag lag ... FUNDAMENTALS 4/E 301 iii PREFACE TO THE INSTRUCTOR This Instructor’s Manual is intended to accompany the fourth edition of Electric Machinery Fundamentals To make this manual easier to use, it has been made ... ag lag + H right lright + H top ltop + H left lleft + H bottom lbottom FTOT = ( 398 kA ⋅ t/m )( 0.0006 m ) + ( 410 A ⋅ t/m )( 0.40 m ) + ( 240 A ⋅ t/m )(0.40 m ) FTOT = 278.6 + 164 + 288 = 691...

Ngày tải lên: 05/08/2014, 20:22

... )( ) Therefore, the total reluctance of the core is RTOT = Rstator + Rair gap + Rrotor + Rair gap RTOT = 62.8 + 221 + 5.2 + 221 = 510 kA ⋅ t/Wb The required MMF is FTOT = φ RTOT = (0.00192 Wb )( ... of 1.2 T, the relative permeability µ r of the rotor is 3800, so the rotor reluctance is Rrotor = lrotor 0.04 m = = 5.2 kA ⋅ t/Wb −7 µstator Arotor (3800 ) 4π × 10 H/m (0.04 m )( 0.04 m ) ( ) ... T, the relative permeability µ r of the stator is about 3800, so the stator reluctance is Rstator = lstator 0.48 m = = 62.8 kA ⋅ t/Wb −7 µstator Astator (3800 ) 4π × 10 H/m (0.04 m )( 0.04 m )...

Ngày tải lên: 05/08/2014, 20:22

... decreased by a factor of more than 80 2-15 A 5000-VA 480/120-V conventional transformer is to be used to supply power from a 600-V source to a 120-V load Consider the transformer to be ideal, and ... 7.94 kΩ Note how easy it was to solve this problem in per-unit, compared with Problem 2-10 above 2-12 An autotransformer is used to connect a 13.2-kV distribution line to a 13.8-kV distribution ... VS A 5000-VA 480/120-V conventional transformer is to be used to supply power from a 600-V source to a 480-V load Consider the transformer to be ideal, and assume that all insulation can handle...

Ngày tải lên: 05/08/2014, 20:22

... generator What is the power factor of the generator? (c) With the switch closed, find the real power P, reactive power Q, and apparent power S supplied by the generator What is the power factor ... charging capacitor C), and vload(t) will be volts However, capacitor C charges up through resistor R, and when the voltage vC(t) builds up to the breakover voltage of D1, the DIAC will start to conduct ... sensitive to variations in the input voltage v ac ( t ) For example, suppose the peak value of the input voltage were to decrease Then the time that it takes capacitor C1 to charge up to the breakover...

Ngày tải lên: 05/08/2014, 20:22

... bottom portion of transformer T1 to the load At that time, a voltage will be applied to the bottom part of the transformer which is positive at the top of the winding with respect to the bottom ... the capacitor charges up to a high enough voltage to decrease the current below IH If we ignore resistor R (because it is so much larger than RLOAD), the capacitor charges through resistor RLOAD ... that the capacitor must be fully charged before SCR1 can be forced to turn off, then the time required would be the time to charge the capacitor The capacitor charges through resistor R1, and the...

Ngày tải lên: 05/08/2014, 20:22

... available to these early motors? (b) For a given motor operating at a constant flux density B, how would the core losses of the motor running at 25 Hz compare to the core losses of the motor running ... machine has the rotor and stator magnetic fields shown in Figure P4-1, what is the direction of the induced torque in the machine? Is the machine acting as a motor or generator? SOLUTION Since ... of a motor-generator set consisting of a synchronous motor driving a synchronous generator How many poles should each of the two machines have in order to convert 50-Hz power to 60-Hz power? SOLUTION...

Ngày tải lên: 05/08/2014, 20:22

... generators to supply 5.31 MW at 60 Hz, the no-load frequencies of Generator and Generator would have to be adjusted to 62.12 Hz, and the no-load frequency of Generator would have to be adjusted to ... applied to the shaft of this generator? Express your answer both in newton-meters and in pound-feet SOLUTION To get the applied torque, we must know the input power The input power to this generator ... happens to the generator How much reactive power does the generator supply now? (d) With the diesel generator now supplying real power to the power system, what happens to the generator as its...

Ngày tải lên: 05/08/2014, 20:22

... questions: (a) What is the output torque of this motor? Express the answer both in newton-meters and in pound-feet (b) What must be done to change the power factor to 0.8 leading? Explain your answer, ... factor can be found from the total real and reactive power supplied to the load PTOT = P + P2 = 299 kW + 120 kW = 419 kW QTOT = Q1 + Q2 = 145 kVAR + 115 kVAR = 260 kVAR The overall power factor ... be if the power factor is adjusted to 0.8 leading? SOLUTION (a) If this motor is assumed lossless, then the input power is equal to the output power The input power to this motor is PIN = 3VT I...

Ngày tải lên: 05/08/2014, 20:22

... S,g A I V φ A Vφ jX I S,m A E A,m Generator Motor (b) The power supplied by the generator to the motor will be constant as the field current of the motor is varied The 10% increase in flux will ... this motor at full load? (f) What is the output torque of the motor at the rated conditions? Express the answer both in newtonmeters and in pound-feet SOLUTION The base quantities for this motor ... the motor is increased by 10 percent, what happens to the terminal voltage of the power system? What is its new value? (c) What is the power factor of the motor after the increase in motor flux?...

Ngày tải lên: 05/08/2014, 20:22

... below: 7-10 For the motor of Problem 7-7, how much additional resistance (referred to the stator circuit) would it be necessary to add to the rotor circuit to make the maximum torque occur at starting ... rotor resistance R2 (b) Find τ max , smax , and the rotor speed at maximum torque for this motor (c) Find the starting torque of this motor (d) What code letter factor should be assigned to ... stator power factor (c) The rotor power factor (d) The stator copper losses PSCL (e) The air-gap power PAG (f) The power converted from electrical to mechanical form Pconv (g) The induced torque...

Ngày tải lên: 05/08/2014, 20:22

... inserting external resistors into the rotor circuit, explain what happens to the following: (a) Slip s (b) Motor speed nm (c) The induced voltage in the rotor (d) The rotor current (e) τ ind (f) ... changed to 275 rad/s, what would happen to the current flow into or out of the machine? (d) If the speed of the rotor were changed to 225 rad/s, what would happen to the current flow into or out ... used to connect the induction motor to the infinite bus, what will the starting current of the motor be? What will the motor’s terminal voltage be on starting? (c) If an ideal 1.4:1 step-down autotransformer...

Ngày tải lên: 05/08/2014, 20:22

... MATLAB program to plot the torque-speed characteristic of this motor is shown below: 228 % M-file: prob9_13.m % M-file to create a plot of the torque-speed curve of the % the series dc motor in Problem ... program to plot the torque-speed characteristic of this motor is shown below: % M-file: series_ts_curve.m % M-file to create a plot of the torque-speed curve of the % the series dc motor in Problem ... ('\bfCumulatively-Compounded DC Motor Torque-Speed Characteristic'); axis([0 125 800 1250]); grid on; The resulting plot is shown below: Compare this torque-speed curve to that of the shunt motor in Problem 9-7...

Ngày tải lên: 05/08/2014, 20:22

... machine To make a practical series motor out of this machine, it would be necessary to include 20 to 30 series turns instead of 12 9-20 An automatic starter circuit is to be designed for a shunt motor ... allowed to vary from to 30 Ω and the generator’s speed is allowed to vary from 1500 to 2000 r/min, what are the maximum and minimum no-load voltages in the generator? SOLUTION (a) If the generator ... flux in the motor will be very small A MATLAB program to calculate the torque-speed characteristic of this motor is shown below: % M-file: prob9_19.m % M-file to create a plot of the torque-speed...

Ngày tải lên: 05/08/2014, 20:22

... connected to a shunt dc machine, forming a motorgenerator set, as shown in Figure P9-11 The dc machine is connected to a dc power system supplying a constant 240 V, and the ac machine is connected to ... there is not enough power to make up the rotational losses The motor will slow down5 10-4 Use MATLAB to calculate and plot the torque-speed characteristic of the motor in Problem 10-1, ignoring ... compounded dc generator in Problem 9-28 and the shunt dc generators in Problem 9-25 (d) 9-29 A cumulatively compounded dc generator is operating properly as a flat-compounded dc generator The machine...

Ngày tải lên: 05/08/2014, 20:22