EE321/ECE595 Spring 2012
Homework 9
Problem 1 Rotating MMF
The winding function of the a and bphase stator windings of a machine are
given by was = 100 cos(4 s ) and wbs = 250 sin(4 s ) . The aphase current of the machine is
given by i as = 10 cos( e t
ECE321/ECE595 Spring 2012 HW#9
Problem 1
(
)
(
)
was = 100 cos 4 s
wbs = 250 sin 4 s
ias = 10 cos e t +
B = 1.2 cos e t +
8
8
4 s
7
0 := 4 10
Expanding B we have
B = 1.2 cos e t +
Also
B=
F=
F
g
0
g
0
B
cos( 4 s) + 1.2 sin e t + 8 sin( 4 s)
8
Finally
F
ECE321/ECE595
Homework 8
Problem 1 Hysteresis Current Control
Consider a machine with an armature resistance of 1 , a voltage constant of 0.05
Vs, and an armature inductance of 2 mH. Suppose it is fed from a dc source of 20 V,
using a chopper circuit with
EE321 Spring 2011 HW7
Problem 1
Buck Converter Operation
Consider a machine with the following parameters:
ra := 0.1
kv := 0.2
The machine is fed using a buck converter with the following parameters
vfsw := 2.4
vfd := 2.0
vdc := 125
d := 0.7
The machine i
EE321 ABET Exam
Spring 2012
You may establish credit for ABET objectives (by answering the following
questions).
1.)
Objective 1. Ability to Analyze / Design Electromagnetic Devices.
A solenoid is an electromechanical device used for actuation. In this si
EE321 Spring 2012
Homework 7
Problem 1 Buck converter operation
Consider the example on page 56 of the lecture notes. Suppose the dc voltage is
changed to 125 V and the speed to 400 rad/s. Find the average armature current, the
average switch current, the
EE321 Spring 2012, HW #6
Problem 1
ra := 8
kv := 0.01
6
K := 5 10
va := 6
kv ( va kv r)
ra
= K r
Set Te = Tl
va
r := kv
2
kv + K ra
r = 428.571
rad/s
Problem 2
ra := 10
Rf := 50
LAF := 0.5
Va := 25
Vf := 25
Part 1  Stall Torque
i f :=
i a :=
Vf
Rf
Va
ra
EC32L4ECE595 Exam 3
Spring2012
Solution
Notes: You must show work for credlt
This exam has 5 problems and 13 pages.
Note tat problems 2r3, anil4 have different specifications depending on
you are in ECE321 or ECE595.
Remember to always work easier problem
5, ^1;ot'l
EeE32fC8595 Exm2
Sprine 2012
Nb'tss.r
You mus.t show work for crdi'
This exam has 5 problems and 1.4 pages.
Note that problems 2 and 3 have different specifications depending on if you
are in ECE321 or ECE595
Remembr io alw*ys work easier pro
E;CEgl'llECEs9s Exam
Spring 2012
1
Notes: You must show work for credit
This exam has 5 problems and 12 pages.
Note that problems 11 3, and 5 have different specifications depending on
you are in ECE321 orECE595
Good luck!
if
r)
15
pts.
Consider a Hfield
EE321 HW#8
Problem 1
ra := 1
kv := 0.05
3
Laa := 2 10
ia :=
Tedes
kv
vdc := 20
vfsw := 1
Tedes := 0.1
vfd := 0.8
fmxdes := 30 10
3
ia = 2
Manipulating the expression in the notes we have
(
)
fsw r , h :=
(vfd + ra ia + kv r) (vdc vfsw ra ia kv r)
2 h Laa
Solutions to Exam 1 Electromechanical Motion Devices ECE 321
Course Instructor: Dr. Scott Sudho TA: Harish Suryanarayana February 7th, 2008
1
Problem 1
H = 10ax + 20ay 5az
The H eld can be written as (1)
The vector connecting the point [5, 2, 1] to [4, 2
ECE321. Fall 2009. Exam 2 Solution Outline 1a) False 1b) True 1c) True 1d) False 1e) True 1f) False 1g) True 1h) True 1i) False 1j) True Problem 2 n as = 100 sin 8sm  2 3
5 pts
P = 16
8 sm 1 was = n as dsm  n as dsm 2 0 0
8 1 2 was = 100 sin 8sm  d
CE32LECE595 Exam 5
Spring 2012
Notes:
This exam has 33 problems worth 3 pts each. Your name is worth I pt.
Answer easy problem first!
1)
What are the physical laws that result in Kirchoff
magnetic equivalent circuits?
Ar4e
I
2)
rWhat physical
re's L o; ,
EE321 Spring 2017
Homework 1
Problem 1 Review of lineintegral and application to MMF drop.
Consider a Cartesian coordinate system (x,y,z). Suppose a uniform Hfield of 1 A/m
exists in the direction of the yaxis. Calculate the MMF drop from the point (1
Lecture Set 0
ECE321/ECE51012(ECE595)
Electromechanical Motion Devices/
Electromechanics
S.D. Sudhoff
Spring 2017
Courses Meeting Together
Courses
ECE321 Live cfw_321L
ECE321 Video cfw_321V
ECE595 On Campus cfw_595C
ECE595 Off Campus Pro Ed cfw_595P
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EE321 Spring 2012
Homework 10
Problem 1 Phase Inductance
Suppose the winding function of aphase of the stator is given by
was =
2
P
N s cos sm
P
2
and the winding function of the bphase of the rotor is given by
wbr =
2
P
N r sin rm
P
2
Express the mut
EE321 Spring 2011
Homework #11
Problem 1
Machine Parameters
rs := 3
m := 0.17
3
Lss := 10 10
N := 3
P := 4
Load
2
r P
TL( r) := 2
200
2.3
Source
vs := 100
v := 0
vq :=
()
2 vs cos v
()
vd := 2 vs sin v
Ok  lets solve the problem
(
)
rs vq r m r Ls
EE321 Spring 2012
Homework 11
Problem 1 Brushless DC Operation from a Voltage Source
A three phase brushless DC machine has the following parameters: rs = 3 , Lss = 10 mH,
m = 0.17 Vs, P = 4 . It is operating from an inverter and the control is such that
EE321 Spring 2012
Homework #12
Problem 1
500 e
Xphasor :=
5+
1
10
( 100j) +
Xphasor = 16.641
(
j
1
300
( 100j)
2
Xphasor 2 = 23.534
)
arg Xphasor = 1.802
x=23.5cos(100t1.802)
If the cosine term were a sine, I simply would have adjusted the phase to get
a
EE321 Spring 2012
Homework 12
Problem 1 Phasor Analysis
Consider the differential equation
5x +
1 dx
1 d2x
+
= 500 2 cos(100t + 1)
10 dt 300 dt 2
where all arguments of the cosine term are in radians. Use phasor analysis to find the steadystate solution
EE321 Spring 2012
Homework #13
Problem 1
We have:
i as = 50 sin( 200 t )
i bs = 50 cos( 200 t )
Now, we will also have
(
)
(
)
was = W cos 2 sm
wbs = W sin 2 sm
Thus, the stator MMF is
(
)
Fs = 50 W sin 200 t 2 sm
Whereupon the stator MMF is moving at 100
EE321 Spring 2012
Homework 13
Problem 1 Rotating MMF
Using the configuration we studied in class (Figure 5.21 in text), the stator currents of a 4 pole
machine are given by
ias = 50 sin(200t )
ibs = 50 cos(200t )
The speed of the machine is 500 rpm in th
ECE321/595 Spring 2012
Homework 14
Problem 1 SteadyState Operation
Consider a 2phase machine with the following parameters: rs = 72.5 m , Lls = L'lr = 1.32 mH,
Lm = 20.1 mH, rr' = 41.3 m , and P = 4 . The load torque varies with the speed cubed, and is
5.)
,r
20 pts (2 pts each). Short Answer
a.) Name a physical effect that reduces the accuracy of the coenergy approach to
flrnding force and torque.
h1$erc\
b) Which machine would you use if you wished to have openloop position control?
c)
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S\qp6f'