Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Chapter 2, Problem 3SQ
How may an automatic operation be achieved when a manual motor starter is used?
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Questions:
Q1: Verify that the average power generated equals the average power
absorbed using the simulated values in Table 7-2.
Q2: Verify that the reactive power generated equals the reactive power
absorbed using the simulated values in Table 7-2.
Q3: Why it is important to correct the power factor of a load?
Q4: Find the ideal value of the capacitor theoretically that will result in unity
power factor.
Vs pp (V)
VRIPP (V) VRLC PP (V)
AT (μs)
T (us)
8°
pf
Simulated
14
8.523
7.84
84.850
1000
29.88
0.866
Measured
14
8.523
7.854
82.94
1000
29.85
0.86733
Table 7-2 Power Calculations
Pvs (mW) Qvs (mVAR) PRI (MW) Pay (mW)
Qt (mVAR)
Qc (mYAR)
Simulated
-12.93
-7.428
9.081
3.855
12.27
-4.84
Calculated
-12.936
-7.434
9.083
3.856
12.32
-4.85
Part II: Power Factor Correction
Table 7-3 Power Factor Correction
AT (us)
0°
pf
Simulated
0
0
1
Measured
0
0
1
Questions:
Q1: Verify that the average power generated equals the average power
absorbed using the simulated values in Table 7-2.
Q2: Verify that the reactive power generated equals the reactive power
absorbed using the simulated values in Table 7-2.
Q3: Why it is important to correct the power factor of a load?
Q4: Find the ideal value of the capacitor theoretically that will result in unity
power factor.
Vs pp (V)
VRIPP (V) VRLC PP (V)
AT (μs)
T (us)
8°
pf
Simulated
14
8.523
7.84
84.850
1000
29.88
0.866
Measured
14
8.523
7.854
82.94
1000
29.85
0.86733
Table 7-2 Power Calculations
Pvs (mW) Qvs (mVAR) PRI (MW) Pay (mW)
Qt (mVAR)
Qc (mYAR)
Simulated
-12.93
-7.428
9.081
3.855
12.27
-4.84
Calculated
-12.936
-7.434
9.083
3.856
12.32
-4.85
Part II: Power Factor Correction
Table 7-3 Power Factor Correction
AT (us)
0°
pf
Simulated
0
0
1
Measured
0
0
1
Chapter 2 Solutions
Electric Motor Control
Ch. 2 - If the contacts on a manual starter cannot be...Ch. 2 - If the handle of an installed motor starter is in...Ch. 2 - How may an automatic operation be achieved when a...Ch. 2 - What does the term trip-free mean as it relates to...Ch. 2 - Prob. 5SQCh. 2 - Prob. 6SQCh. 2 - Prob. 7SQCh. 2 - Prob. 8SQCh. 2 - Select the best answer for each of the following....Ch. 2 - Select the best answer for each of the following....
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