139
As the rotor accelerates, the slip frequency decreases. (The slip frequency is the frequency of the voltages and currents induced in
the rotor.) The flux linkage equation is given as V = 4.44Nf, therefore as the slip frequency decreases, the induced
3d BASICS
A ? Y Transformation
for balanced load
Z A = 3Z Y
Balanced 3d Systems
MV ab ? 120 E = MV bc
MV ab ? 240 E = MV ca
MI a ? 120 E = MI b
MI a ? 240 E = MI c
V ab
= 3 V an
Ia
= 3 I ab
MV ab ? 30 E = MV an
MI ab ? 30 E = MI a
S 3?d = 3 V an I
D
a
S
3 BASICS
Y Transformation
for balanced load
Z 3Z Y
Balanced 3 Systems
V ab 120 V bc
V ab 240 V ca
I a 120 I b
I a 240 I c
V ab 
I a 
3 V an 
3 I ab 
V ab 30 V an
I ab 30 I a
S 3 3 V an I a
S 3 3 V ab I ab
S 3 3 V ab I a 30
PER UNIT SYSTEM
SB
.l40
cHAprER
5
FUNDAMENTALS
oF
RoTATTNG MAcHTNEs
The commutator and brush combination converts the AC to a DC voltage in
the case of a DC generator. In the DC motor, each conducting loop on the rotor
is in contact with the applied DC voltage through the c
PROBLEMS
155
DR'I.I. PROEI.EMS
In Drill Problem D5.7, the mmf due to the generator rotor field winding
may be expressed in terms of the rotor position 0. and the peak value of rotor
D5.14
mmf Fr as follows:
Fil :
Fr cos(O

0m)
:
(377t + n/2) radians and
Spring 2000
EE361: MIDTERM EXAM 1
NAME:
STUDENT NUMBER:
This exam is open book and closed notes. Assume f=60 hz and use the constant o=4107
wherever necessary. Be sure to show all work clearly.
1. (20 points) Phasors  3 fundamentals:
A measurement of t
FALL 1995
EE361: EXAM
NAME:
STUDENT NUMBER:
This exam is open book and open notes but all work must be your own. Be sure to show all
work clearly.
1. 5 points  3 Power: Find the real and reactive power delivered to the unbalanced deltaconnected load ske
Fall 1997
EE361: MIDTERM EXAM 2
NAME:
STUDENT NUMBER:
This exam is open book and closed notes. Be sure to show all work clearly.
1. 10 points  Mechanical and Electrical Energy Relationships: A dc motor is rotating at 800
RPM with Ea=1000 V and Ia=10 A. M
Spring 2001
EE361: MIDTERM EXAM 2
NAME:
STUDENT NUMBER:
This exam is open book and closed notes. Be sure to show all work clearly.
1. 25 points  Three Phase Induction Motor: A three phase 25kW 500 V fourpole 60 Hz
induction motor when operating at full
Fall 2002
EE361: Final Exam
NAME:
STUDENT NUMBER:
This exam is open book and closed notes. Be sure to show all work clearly.
1. Phasors and 3 fundamentals (10 points): If the voltage between phase a and b is
vab(t)=325000cos(377t+45) and the line current
Total: 10 points. The formula covers 8 points.
Total: 10 points. 4 points for the calculations. 6 points for the formulas.
Total: 15 points. 5 points for each subproblem.
Total: 15 points. 7.5 points for each subproblem.
Total: 20 points. 5 points for eac
e L appears to be the load. It is not the load because E and
I are 180o out of phase. Therefore L is the active source.
f N appears to be the load. It is the load because I lags 90o
behand E. Therefore M is a reactive source.
Total: 15 points. 2.5 points
Total: 10 points. 3 points off for one mistake, 6 points off for two mistakes.
Total: 10 points. 3 points off for one mistake, 6 points off for two mistakes.
Total: 10 points. 2 points for the figure, 2 points for the formula of voltage, 2
points for each
ECE 325, Fall 2015, Test 2
Problem 1 (40 points): Short answer questions
a. (3 points each) True or false for each of the following statements?
1) Analogous to the electrical resistance of a conductor, the magnetic reluctance Rm of an iron
core placed in
ECE 325, Fall 2016, Test 1
Problem 1 (35 points, 5 points each): Circle ALL correct statements (reasons are NOT required)
a. For long distance power transmission, HVAC is always a more economical option than HVDC.
(At present, the crossover point for HVD
Spring 1997
EE361: MIDTERM EXAM 3
NAME:
STUDENT NUMBER:
This exam is open book and closed notes. Be sure to show all work clearly.
1. Synchronous machine (20 points). A threephase synchronous machine is connected to a
load through a lossless short transm
Spring 1997
EE361: MIDTERM EXAM 3
This exam is open book and closed notes. Be sure to show all work clearly.
1. Admittance Matrix and Load Flow Equations (25 points). Consider the 3bus system
sketched below. Find (a) the admittance matrix, i.e., Ybus and
F all2013
ECE361: MIDTERM EXAM 1
NAME:
STUDENT NUMBER:
325
This exam is closed book and closed notes. A ssumef=60 hz and use the constant ,Ua=4n:x10 7
Him wherever necessary . B e sure to show all work clearly .
1. 20 points  Inductance calculation: I n
a'XlAJlOKL
I_'__IJ
Spring 2000
EEJl: Ml'DTERM EXAM 1
NAME:
STUDENT NUMBER:
This exam is open book and closed notes. Assthef=6O h: and use the constant lg=4zx102
wherever necessary. Be sure to show all work clearly.
1.(20 points) Phnsors  399 funda
5.2
a. F NI (600)(8) 4800 A t
Rcenter
gc
1 10 3
62,819
0 Ac (4 10 7 )( )( 2.5) 2 ( 2.54) 2 10 4
gs
0.5 10 3
78,524
0 As (4 10 7 )( 0.5 5.0)(2.54) 2 10 4
RT Rcenter Rshell 62,819 78,524 141,343
F
4800
T
33.96mWb
RT 141,343
Rshell
b. L / I N T / I (
ECE 325, Fall 2015, Final Exam
Name_
The test has 120 points. Please finish as many problems as possible for more points.
Problem 1 (40 points): Short answer questions
a. (3 points each) True or false (circle one) for these statements about a 4pole squir