Electric machinery fundamentals
5th Edition
ISBN: 9780073529547
Author: Chapman, Stephen J.
Publisher: MCGRAW-HILL HIGHER EDUCATION
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Chapter 1, Problem 1.14Q
To determine
To discuss: The reason for considering a linear machine a good example of the behavior observed in the real dc machine.
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Students have asked these similar questions
Derive the EMF and Torque equations of DC machines from the first principles.
QUESTION 1
a) Write down three (3) factors that will determine the induced torque in a DC machine.
b) Explain why higher voltage applied to a motor doesn't always mean that it will have a
higher induced torque. You can give an example of the scenario to answer this question.
c) When a motor is powered up and rotates, it will induce an internal generated voltage.
Is this statement true or false? Justify your answer.
d) For the core design shown in Fig. 1:
i.
Design the magnetic circuit model. Indicate clearly for each part that you use
in the magnetic circuit which part of the core is represented.
ii.
Predict what will happen to the total reluctance if the depth is increased.
Justify your answer.
rl
r2
r4
9 cm
9 cm
-25 cm
15 cm
to
-25 cm-
9 cm
2 A
200 turns
-0.04 cm
25 cm
9 ém
The resistance of the field winding(copper wire) of a
DC machine is 0.25 ohm at 25°C. When operating at
full-load, the temperature of the winding is 75 °C. The
temperature coefficient of resistance of copper is
0.00427 per °C at 0°C. Find the resistance of the field
winding at full-load.
Chapter 1 Solutions
Electric machinery fundamentals
Ch. 1 - What is torque? What role does torque play in the...Ch. 1 - What is Amperes law?Ch. 1 - What is magnetizing intensity? What is magnetic...Ch. 1 - How does the magnetic circuit concept aid in the...Ch. 1 - What is reluctance?Ch. 1 - What is a ferromagnetic material? Why is the...Ch. 1 - How does the relative permeability of a...Ch. 1 - Prob. 1.8QCh. 1 - What are eddy current losses? What can be done to...Ch. 1 - Why are all cores exposed to ac flux variations...
Ch. 1 - What is Faraday law?Ch. 1 - What conditions are necessary for a magnetic field...Ch. 1 - What conditions are necessary for a magnetic field...Ch. 1 - Prob. 1.14QCh. 1 - The linear machine in Figure 1-19 is running at...Ch. 1 - Just how does a decrease in flux produce an...Ch. 1 - Will current be leading or lagging voltage in an...Ch. 1 - What are real, reactive, and apparent power? What...Ch. 1 - What is power factor?Ch. 1 - Prob. 1.1PCh. 1 - A flywheel with a moment of inertia of 4kgm2 is...Ch. 1 - A force of 10 N is applied to a cylinder of radius...Ch. 1 - A motor is supplying 50Nm of torque to its load....Ch. 1 - A ferromagnetic core is shown in Figure P1-2. The...Ch. 1 - A ferromagnetic core with a relative permeability...Ch. 1 - A two-legged core is shown in Figure P1-4. The...Ch. 1 - A core with three legs is shown in Figure P1-5....Ch. 1 - A two-legged core is shown in Figure P1-4. The...Ch. 1 - A wire is shown in Figure P1-7 that is moving in...Ch. 1 - Repeat Problem 1-10 for the wire in Figure P1-8.Ch. 1 - Prob. 1.12PCh. 1 - A core with three legs is shown in Figure P1-10....Ch. 1 - A two-legged magnetic core with an air gap is...Ch. 1 - A transformer core with an effective mean path...Ch. 1 - The core shown in Figure P1-2 has the flux shown...Ch. 1 - Prob. 1.17PCh. 1 - Prob. 1.18PCh. 1 - Prob. 1.19PCh. 1 - Demonstrate that Equation (1-59) can be derived...Ch. 1 - Prob. 1.21PCh. 1 - Prob. 1.22PCh. 1 - For the linear machine of Problem 1-22: When this...
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- The armature reaction of DC machines is less under no load condition. Select one: O True O Falsearrow_forwardDerive the EMF and Torque equation of the DC machines from the first principles.arrow_forward• A DC shunt machine while running as generator develops a voltage of 250 V at 1000 r.p.m. on no-load. It has armature resistance of 0.5 ohm and field resistance of 250 ohm. When the machine runs as motor, input to it at no-load is 4 A at 250 V. Calculate the speed and efficiency of the machine when it runs as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4 %arrow_forward
- At loaded condition, the effect of armature reaction is more in DC machines. Select one: O True Falsearrow_forwardTopic Electrical Machines - Magnetic & E... For a coil, each turn faces (2t4 – t³ – 2t) milliwebers of flux. The value of induced EMF in coil for 100 turns coil at 2 sec is, (in Volts).arrow_forwardThe first blank: Choose... different equal low enough The second blank: Choose... equal different high enough The third blank: Choose... salient pole non-salient pole all types ofarrow_forward
- What are the different losses which occur in a DC machine. * Your answerarrow_forward) A d.c. shunt machine while running as generator develops a voltage of 240 V at 1000 rp.m. on no-load It has armature resistance of 0.52 and field resistance of 250 92. When the machine runs as motor, input to it at no-load ts 4 A at 240 V. Calculate the speed and efficiency of the machine when it runs as a motor taking 40 A at 240 V. Armature reaction weakens the field by 6%arrow_forwardThe introduction of interpoles in between the main pole improves the performance of dc machines, because .................? (A) the interpole produces additional flux to augment the developed torque (B) the flux waveform is improved with reduction in harmonics (C) the inequality of air flux on the top and bottom halves of armature is removed (D) a counter Emf is induced in coil undergoing commutationarrow_forward
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