Understanding Motor Controls
4th Edition
ISBN: 9781337798686
Author: Stephen L. Herman
Publisher: Delmar Cengage Learning
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Chapter 34, Problem 7RQ
To determine
Identify the type of a solid-state component that is generally used to control AC voltage.
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Students have asked these similar questions
Recall that the CWH equation involves two important assumptions. Let us investigate how these
assumptions affect the accuracy of state trajectories under the control inputs optimized in (a) and (b).
(c.1): Discuss the assumptions about the chief and deputy orbits that are necessary for deriving CWH.
PROBLEM 2.50
1.8 m
The concrete post (E-25 GPa and a
=
9.9 x 10°/°C) is reinforced with six
steel bars, each of 22-mm diameter (E, = 200 GPa and a, = 11.7 x 10°/°C).
Determine the normal stresses induced in the steel and in the concrete by a
temperature rise of 35°C.
6c
"
0.391 MPa
240 mm
240 mm
6₁ =
-9.47 MPa
For some viscoelastic polymers that are subjected to stress relaxation tests, the stress decays with
time according to
a(t) = a(0) exp(-4)
(15.10)
where σ(t) and o(0) represent the time-dependent and initial (i.e., time = 0) stresses, respectively, and t and T denote
elapsed time and the relaxation time, respectively; T is a time-independent constant characteristic of the material. A
specimen of a viscoelastic polymer whose stress relaxation obeys Equation 15.10 was suddenly pulled in tension to
a measured strain of 0.5; the stress necessary to maintain this constant strain was measured as a function of time.
Determine E (10) for this material if the initial stress level was 3.5 MPa (500 psi), which dropped to 0.5 MPa (70
psi) after 30 s.
Chapter 34 Solutions
Understanding Motor Controls
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