Electric Motors and Control Systems
2nd Edition
ISBN: 9780073373812
Author: Frank D. Petruzella
Publisher: McGraw-Hill Education
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Question
Chapter 1.2, Problem 11RQ
To determine
Three motor control devices that are rated by NEMA.
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2. Express the following complex numbers in rectangular form.
(a) z₁ = 2еjл/6
(b) Z2=-3e-jπ/4
(c) Z3 =
√√√3e-j³/4
(d) z4 = − j³
A prismatic beam is built into a structure. You can consider the boundary conditions at A and B to be
fixed supports. The beam was originally designed to withstand a triangular distributed load, however,
the loading condition has been revised and can be approximated by a cosine function as shown in the
figure below. You have been tasked with analysing the structure. As the beam is prismatic, you can
assume that the bending rigidity (El) is constant.
wwo cos
2L
x
A
B
Figure 3: Built in beam with a varying distributed load
In order to do this, you will:
a. Solve the reaction forces and moments at point A and B.
Hint: you may find it convenient to use the principal of superposition.
(2%)
b. Plot the shear force and bending moment diagrams and identify the maximum shear force
and bending moment.
(2%)
c. Develop an expression for the vertical deflection. Clearly state your expression in terms of x.
(1%)
Question 1: Beam Analysis
Two beams (ABC and CD) are connected using a pin immediately to the left of Point C. The pin acts
as a moment release, i.e. no moments are transferred through this pinned connection. Shear forces
can be transferred through the pinned connection. Beam ABC has a pinned support at point A and a
roller support at Point C. Beam CD has a roller support at Point D. A concentrated load, P, is applied
to the mid span of beam CD, and acts at an angle as shown below. Two concentrated moments, MB
and Mc act in the directions shown at Point B and Point C respectively. The magnitude of these
moments is PL.
Moment Release
A
B
с
°
MB = PL
Mc=
= PL
-L/2-
-L/2-
→
P
D
Figure 1: Two beam arrangement for question 1.
To analyse this structure, you will:
a) Construct the free body diagrams for the structure shown above. When constructing your
FBD's you must make section cuts at point B and C. You can represent the structure as three
separate beams. Following this, construct the…
Chapter 1 Solutions
Electric Motors and Control Systems
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Ch. 1.2 - Prob. 1RQCh. 1.2 - Prob. 2RQCh. 1.2 - Prob. 3RQCh. 1.2 - List the seven steps involved in a...Ch. 1.2 - Prob. 5RQCh. 1.2 - Prob. 6RQCh. 1.2 - How are the standards contained in the...Ch. 1.2 - Explain the difference between a Code Article and...Ch. 1.2 - Prob. 9RQCh. 1.2 - Prob. 10RQCh. 1.2 - Prob. 11RQCh. 1.2 - Prob. 12RQCh. 1.2 - The voltage between the frame of a 3-phase 208...Ch. 1.2 - Prob. 2TCh. 1.2 - Prob. 3TCh. 1.2 - A hot stick is to be used to open a...Ch. 1.2 - An employee is contemplating using his lockoutlock...Ch. 1.2 - Prob. 1DTCh. 1.2 - Prob. 2DTCh. 1.2 - Why can birds safely rest on high-voltage...
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