Electrical Transformers and Rotating Machines
4th Edition
ISBN: 9781305494817
Author: Stephen L. Herman
Publisher: Cengage Learning
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Textbook Question
Chapter 2, Problem 1RQ
What determines the polarity of magnetism when current flows through a conductor?
Expert Solution & Answer
To determine
The factor which determines the polarity of magnetism when current flows through the conductor.
Explanation of Solution
According to the basic law of electricity, a magnetic field is created around the conductor whenever the current flows through it. The direction of flow current tells the polarity of the magnetic field and the quantity of current tells the strength of the magnetic field. In addition to the direction of current flow, left hand rule is used to determine the polarity of the magnetic field.
Thus, the direction of the current flow determines the polarity of the magnetism when current flows through the conductor.
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3.
9.
10.
The centrifugal tension in belts
(a) increases power transmitted
(b) decreases power transmitted
(c) have no effect on the power transmitted
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When the belt is stationary, it is subjected to some tension, known as initial tension. The value of this
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(a) tension in the tight side of the belt
(b) tension in the slack side of the belt
(c) sum of the tensions in the tight side and slack side of the belt
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The relation between the pitch of the chain (p) and pitch circle diameter of the sprocket (d) is given by
60°
(a) p=d sin
(c) p=d sin
(120°
T
where T Number of teeth on the sprocket.
90°
(b) p=d sin
T
180°
(d) p=d sin
T
OBJECTIVE TYPE QUESTIONS
1.
The maximum fluctuation of energy is the
2.
(a) sum of maximum and minimum energies
(b) difference between the maximum and minimum energies
(c) ratio of the maximum energy and minimum energy
(d) ratio of the mean resisting torque to the work done per cycle
In a turning moment diagram, the variations of energy above and below the mean resisting torque line
is called
(a) fluctuation of energy
(b) maximum fluctuation of energy
(c) coefficient of fluctuation of energy
(d) none of the above
Chapter 16: Turning Moment Diagrams and Flywheel 611
The ratio of the maximum fluctuation of speed to the mean speed is called
3.
(a) fluctuation of speed
(c) coefficient of fluctuation of speed
4.
(b) maximum fluctuation of speed
(a) none of these
The ratio of the maximum fluctuation of energy to the.......... is called coefficient of fluctuation of
energy.
(a) minimum fluctuation of energy
(b) work done per cycle
The maximum fluctuation of energy in a flywheel is equal to
5.…
OBJECTIVE TYPE QUESTIONS
1.
The velocity ratio of two pulleys connected by an open belt or crossed belt is
2.
(a) directly proportional to their diameters
(b) inversely proportional to their diameters
(c) directly proportional to the square of their diameters
(d) inversely proportional to the square of their diameters
Two pulleys of diameters d, and d, and at distance x apart are connected by means of an open belt
drive. The length of the belt is
(a)(d+d₁)+2x+
(d₁+d₂)²
4x
(b)(d₁-d₂)+2x+
(d₁-d₂)²
4x
(c)(d₁+d₂)+ +2x+
(d₁-d₂)²
4x
(d)(d-d₂)+2x+
(d₁ +d₂)²
4x
3.
In a cone pulley, if the sum of radii of the pulleys on the driving and driven shafts is constant, then
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(b) cross belt drive is recommended
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(d) the drive is recommended depending upon the torque transmitted
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4.
(a) decreases
5.
(b) increases
(c) does not change
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Chapter 2 Solutions
Electrical Transformers and Rotating Machines
Ch. 2 - What determines the polarity of magnetism when...Ch. 2 - What determines the strength of the magnetic field...Ch. 2 - Prob. 3RQCh. 2 - How many lines of magnetic flux must be cut in 1 s...Ch. 2 - Prob. 5RQCh. 2 - Into how many time constants is an exponential...Ch. 2 - Each time constant of an exponential curve is...Ch. 2 - An inductor has an inductance of 0.025 H and a...Ch. 2 - Prob. 9RQCh. 2 - What electronic component is often used to prevent...
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