All Matches

Solution Library

Expert Answer

Textbooks

Search Textbook questions, tutors and Books

Oops, something went wrong!

Change your search query and then try again

Result Not Found

Books FREE
Tutors
Study Help
Ask a Question

Search
Sign In
Register

study help
engineering
electrical engineering

Questions and Answers of Electrical Engineering

Winding 1 in the loudspeaker of Problem 3.25 (Figure) is replaced by a permanent magnet as shown in Figure. The magnet can be represented by the linear characteristic Bm = ?R (Hm ? Hc). a. Assuming
Figure shows a circularly symmetric system in which a moveable plunger (constrained to move only in the vertical direction) is supported by a spring of spring constant K = 5.28 N/m. The system is
The plunger of a solenoid is connected to a spring. The spring force is given by f = K0 (0.9a – x), where x is the air-gap length. The inductance of the solenoid is of the form L = L0 (1 – x/a),
Consider the solenoid system of Problem 3.30. Assume the following parameter values: L0 = 4.0mH a = 2.2cm R = 1.5Ω K0 = 3.5N/cm. The plunger has mass M = 0.2 kg. Assume the coil to be connected to
The solenoid of Problem 3.31 is now connected to a dc voltage source of magnitude 6 V.a. Find the equilibrium displacement X0.b. Write the dynamic equations of motion for the system.c. Linearize
Consider the single-coil rotor of Example 3.1. Assume the rotor winding to be carrying a constant current of I = 8 A and the rotor to have a moment of inertia J = 0.0125 kg ∙ m2.a. Find the
Consider a solenoid magnet similar to that of Example 3.10 (Figure) except that the length of the cylindrical plunger is reduced to a + h. Derive the dynamic equations of motion of the system.
The nameplate on a 460-V, 50-hp, 60-Hz, four-pole induction motor indicates that its speed at rated load is 1755 r/min. Assume the motor to be operating at rated load.a. What is the slip of the
Stray leakage fields will induce rotor-frequency voltages in a pickup coil mounted along the shaft of an induction motor. Measurement of the frequency of these induced voltages can be used to
A three-phase induction motor runs at almost 1198 r/min at no load and 1112 r/min at full load when supplied from a 60-Hz, three-phase source.a. How many poles does this motor have?b. What is the
Linear induction motors have been proposed for a variety of applications including high-speed ground transportation. A linear motor based on the induction-motor principle consists of a car riding on
A three-phase, variable-speed induction motor is operated from a variable frequency, variable-voltage source which is controlled to maintain constant peak air-gap flux density as the frequency of the
Describe the effect on the torque-speed characteristic of an induction motor produced by(a) Halving the applied voltage and(b) Halving both the applied voltage and the frequency. Sketch the resultant
Figure shows a system consisting of a three-phase wound-rotor induction machine whose shaft is rigidly coupled to the shaft of a three-phase synchronous motor. The terminals of the three-phase rotor
A system such at that shown in Figure is used to convert balanced 50-Hz voltages to other frequencies. The synchronous motor has four poles and drives the interconnected shaft in the clockwise
A three-phase, eight-pole, 60-Hz, 4160-V, 1000-kW squirrel-cage induction motor has the following equivalent-circuit parameters in ohms per phase Y referred to the stator: R1 = 0.220 R2 = 0.207 X1 =
A three-phase, Y-connected, 460-V (line-line), 25-kW, 60-Hz, four-pole induction motor has the following equivalent-circuit parameters in ohms per phase referred to the stator: R1 = 0.103 R2 = 0.225
Consider the induction motor of Problem 6.10.a. Find the motor speed in r/min corresponding to the rated shaft output power of 25 kW.b. Similarly, find the speed in r/min at which the motor will
A 15-kW, 230-V, three-phase, Y-connected, 60-Hz, four-pole squirrel-cage induction motor develops full-load internal torque at a slip of 3.5 percent when operated at rated voltage and frequency. For
The induction motor of Problem 6.13 is supplied from a 230-V source through a feeder of impedance Zf = 0.05 + j0.14 ohms. Find the motor slip and terminal voltage when it is supplying rated load.
A three-phase induction motor, operating at rated voltage and frequency, has a starting torque of 135 percent and a maximum torque of 220 percent, both with respect to its rated-load torque.
When operated at rated voltage and frequency, a three-phase squirrel-cage induction motor (of the design classification known as a high-slip motor) delivers full load at a slip of 8.7 percent and
A 500-kW, 2400-V, four-pole, 60-Hz induction machine has the following equivalent-circuit parameters in ohms per phase Y referred to the stator: R1 = 0.122 R2 = 0.317 X1 = 1.364 X2 = 1.32 Xm = 45.8.
Write a MATLAB script to plot the efficiency as a function of electric power output for the induction generator of Problem 6.17 as the slip varies from -0.5 to -3.2 percent. Assume the generator to
For a 25-kW, 230-V, three-phase, 60-Hz squirrel-cage motor operating at rated voltage and frequency, the rotor I2R loss at maximum torque is 9.0 times that at full-load torque, and the slip at
A squirrel-cage induction motor runs at a full-load slip of 3.7 percent. The rotor current at starting is 6.0 times the rotor current at full load. The rotor resistance and inductance is independent
A A-connected, 25-kW, 230-V, three-phase, six-pole, and 50-Hz squirrel-cage induction motor has the following equivalent-circuit parameters in ohms per phase Y: R1 = 0.045 R2 = 0.054 X1 = 0.29 X2 =
The following data apply to a 125-kW, 2300-V, three-phase, four pole, 60-Hz squirrel-cage induction motor: Stator-resistance between phase terminals = 2.23 Ω. No-load test at rated frequency and
Two 50-kW, 440-V, three-phase, six-pole, 60-Hz squirrel-cage induction motors have identical stators. The dc resistance measured between any pair of stator terminals is 0.204 ft. Blocked-rotor tests
A 230-V, three-phase, six-pole, 60-Hz squirrel-cage induction motor develops a maximum internal torque of 288 percent at a slip of 15 percent when operated at rated voltage and frequency. If the
A 75-kW, 50-Hz, four-pole, and 460-V three-phase, wound-rotor induction motor develops full load torque at 1438 r/min with the rotor short-circuited. An external non-inductive resistance of 1.1Ω is
A 75-kW, 460-V, three-phase, four-pole, 60-Hz, wound-rotor induction motor develops a maximum internal torque of 225 percent at a slip of 16 percent when operated at rated voltage and frequency with
Neglecting any effects of rotational and core losses, use MATLAB to plot the internal torque versus speed curve for the induction motor of Problem 6.10 for rated-voltage, rated-frequency operation.
A 100-kW, three-phase, 60-Hz, 460-V, six-pole wound-rotor induction motor develops its rated full-load output at a speed of 1158 r/min when operated at rated voltage and frequency with its slip rings
A 460-V, three-phase, six-pole, 60-Hz, 150-kW, wound-rotor induction motor develops an internal torque of 190 percent with a line current of 200 percent (torque and current expressed as a percentage
The resistance measured between each pair of slip rings of a three-phase, 60-Hz, 250-kW, 16 poles, and wound-rotor induction motor is 49 mΩ. With the slip tings short-circuited, the full-load slip
Consider a separately-excited dc motor. Describe the speed variation of the motor operating unloaded under the following conditions:a. The armature terminal voltage is varied while the field current
A dc shunt motor operating at an armature terminal voltage of 125 V is observed to be operating at a speed of 1180 r/min. When the motor is operated unloaded at the same armature terminal voltage but
For each of the following changes in operating condition for a dc shunt motor, describe how the armature current and speed will vary:a. Halving the armature terminal voltage while the field fluxes
The constant-speed magnetization curve for a 25-kW, 250-V dc machine at a speed of 1200 r/min is shown in Figure. This machine is separately excited and has an armature resistance of 0.14?. This
The dc generator of Problem 7.4 is to be operated at a constant speed of 1200 r/min into a load resistance of 2.5?. a. Using the "spline ( )" function of MATLAB and the points of the magnetization
The dc machine of Problem 7.4 is to be operated as a motor supplied by a constant armature terminal voltage of 250 V. If saturation effects are ignored, the magnetization curve of Figure becomes a
Repeat Problem 7.6 including the saturation effects represented by the saturation curve of Figure. For part (a), set the field current equal to the value required to produce an open-circuit armature
A 15-kW, 250-V, 1150 r/min shunt generator is driven by a prime mover whose speed is 1195 r/min when the generator delivers no load. The speed falls to 1140 r/min when the generator delivers 15 kW
When operated from a 230-V dc supply, a dc series motor operates at 975 r/min with a line current of 90 A. Its armature-circuit resistance is 0.11Ω and its series-field resistance is 0.08Ω. Due to
Consider the long-shunt, 250-V, 100-kW dc machine of Example 7.3. Assuming the machine is operated as a motor at a constant supply voltage of 250-V with a constant shunt-field current of 5.0 A, use
A 250-V dc shunt-wound motor is used as an adjustable-speed drive over the range from 0 to 2000 r/min. Speeds from 0 to 1200 r/min are obtained by adjusting the armature terminal voltage from 0 to
Two adjustable-speed dc shunt motors have maximum speeds of 1800r/min and minimum speeds of 500r/min. Speed adjustment is obtained by field-rheostat control. Motor A drives a load requiring constant
Consider a dc shunt motor connected to a constant-voltage source and driving a load requiring constant electromagnetic torque. Show that if Ea > 0.5Vt (the normal situation), increasing the
A separately-excited dc motor is mechanically coupled to a three-phase, four-pole, 30-kVA, 460-V, cylindrical-pole synchronous generator. The dc motor is connected to a constant 230-V dc supply, and
A 150-kW, 600-V, 600 r/min dc series-wound railway motor has a combined field and armature resistance (including brushes) of 0.125?. The full-load current at rated voltage and speed is 250 A. The
A 25-kW, 230-V shunt motor has an armature resistance of 0.11Ω and a field resistance of 117Ω. At no load and rated voltage, the speed is 2150 r/min and the armature current is 6.35 A. At full load
A 91-cm axial-flow fan is to deliver air at 16.1m3/sec against a static pressure of 120 Pa when rotating at a speed of 1165 r/min. The fan has the following speed-load characteristic. It is proposed
A shunt motor operating from a 230-V line draws a full-load armature current of 46.5 A and runs at a speed of 1300 r/min at both no load and full load. The following data is available on this motor:
A 7.5-kW, 230-V shunt motor has 2000 shunt-field turns per pole, an armature resistance (including brushes) of 0.21?, and a commutating-field resistance of 0.035?. The shunt-field resistance
When operated at rated voltage, a 230-V shunt motor runs at 1750 r/min at full load and at no load. The full-load armature current is 70.8 A. The shunt field winding has 2000 turns per pole. The
A 230-V dc shunt motor has an armature-circuit resistance of 0.23Ω. When operating from a 230-V supply and driving a constant-torque load, the motor is observed to be drawing an armature current of
A common industrial application of dc series motors is in crane and hoist drives. This problem relates to the computation of selected motor performance characteristics for such a drive. The specific
A 25-kW, 230-V shunt motor has an armature resistance of 0.064Ω and a field-circuit resistance of 95Ω. The motor delivers rated output power at rated voltage when its armature current is 122 A.
The manufacturer's data sheet for a permanent-magnet dc motor indicates that it has a torque constant Km = 0.21 V/(rad/sec) and an armature resistance of 1.9Ω. For a constant applied armature
Measurements on a small permanent-magnet dc motor indicate that it has an armature resistance of 4.6Ω. With an applied armature voltage of 5 V, the motor is observed to achieve a no-load speed of
The dc motor of Problem 7.25 will be used to drive a load which requires a power of 0.75 W at a speed of 8750 r/min. Calculate the armature voltage which must be applied to achieve this operating
Repeat Example 8.1 for a machine identical to that considered in the example except that the stator pole-face angle is β = 45°.
In the paragraph preceding Equation 8.1, the text states that "under the assumption of negligible iron reluctance the mutual inductances between the phases of the doubly-salient VRM of Figure b will
A 6/4 VRM of the form of Figure has the following properties: Stator pole angle ? = 30 ?, Rotor pole angle ? = 30 ?, Air-gap length g = 0.35 mm, Rotor outer radius R = 5.1 cm, Active length D = 7 cm.
In Section 8.2, when discussing Figure, the text states: "In addition to the fact that there are not positions of simultaneous alignment for the 6/4 VRM, it can be seen that there also are no rotor
Consider a three-phase 6/8 VRM. The stator phases are excited sequentially, requiting a total time of 15 msec. Find the angular velocity of the rotor in r/min.
The phase windings of the castleated machine of Figure are to be excited by turning the phases on and off individually (i.e., only one phase can be on at any given time). a. Describe the sequence of
Replace the 28-tooth rotor of Problem 8.7 with a rotor with 26 teeth.a. Phase 1 is excited, and the rotor is allowed to come to rest. If the excitation on phase 1 is removed and excitation is applied
Repeat Example 8.3 for a rotor speed of 4500 r/min.
Repeat Example 8.3 under the condition that the rotor speed is 4500 r/min and that a negative voltage of -250 V is used to turn off the phase current.
The three-phase 6/4 VRM of Problem 8.4 has a winding resistance of 0.15Ω/phase and a leakage inductance of 4.5 mH in each phase. Assume that the rotor is rotating at a constant angular velocity of
Assume that the VRM of Examples 8.1 and 8.3 is modified by replacing its rotor with a rotor with 75° pole-face angles as shown in Figure a. All other dimensions and parameters of the VRM are
Consider a two-phase stepper motor with a permanent-magnet rotor such as shown in Figure and whose torque-angle curve is as shown in Figure a. This machine is to be excited by a four-bit digital
Figure shows a two-phase hybrid stepping motor with castleated poles on the stator. The rotor is shown in the position it occupies when current is flowing into the positive lead of phase 1. a. If
Consider a multi-stack, multiphase variable-reluctance stepping motor, such as that shown schematically in Figure, with 14 poles on each of the rotor and stator stacks and three stacks with one phase
A 1-kW, 120-V, 60-Hz capacitor-start motor has the following parameters for the main and auxiliary windings (at starting): Zmain = 4.82 + j7.25Ω main winding, Zaux = 7.95 + j9.21Ω auxiliary
Repeat Problem 9.1 if the motor is operated from a 120-V, 50-Hz source.
Repeat Example 9.2 for slip of 0.045.
A 500-W, four-pole, 115-V, 60-Hz single-phase induction motor has the following parameters (resistances and reactance’s in Ω/phase): Rl, main = 1.68, R2, main = 2.96, Xl, main = 1.87, Xm, main =
Write a MATLAB script to produce plots of the speed and efficiency of the single-phase motor of Problem 9.5 as a function of output power over the range 0 < Pout < 500 W.
At standstill the rms currents in the main and auxiliary windings of a four-pole, capacitor-start induction motor are/main = 20.7 A and Iaux = 11.1 A respectively. The auxiliary-winding current leads
Derive an expression in terms of Q2, main for the nonzero speed of a single-phase induction motor at which the internal torque is zero.
The equivalent-circuit parameters of an 8-kW, 230-V, 60-Hz, four-pole, two-phase, squirrel-cage induction motor in ohms per phase are Rl = 0.253 Xl = 1.14 Xm = 32.7 R2 = 0.446 X2 = 1.30. This motor
The equivalent-circuit parameters of an 8-kW, 230-V, 60-Hz, four-pole, two-phase, squirrel-cage induction motor in ohms per phase are Rl = 0.253 Xl = 1.14 Xm = 32.7 R2 = 0.446 X2 = 1.30. This motor
The induction motor of Problem 9.9 is supplied from an unbalanced two phase source by a four-wire feeder having an impedance Z = 0.32 + j1.5Ω/phase. The source voltages can be expressed as Vα = 235
The equivalent-circuit parameters in ohms per phase referred to the stator for a two-phase, 1.0 kW, 220-V, four-pole, 60-Hz, squirrel-cage induction motor are given below. The no-load rotational loss
A 120-V, 60-Hz, capacitor-run, two-pole, single-phase induction motor has the following parameters: Lmain = 47.2 mH Rmain = 0.38?, Laux = 102 mH Raux = 1.78?, Lr = 2.35?H R r = 17.2??, Lmain, r =
Consider the single-phase motor of Problem 9.13. Write a MATLAB script to search over the range of capacitor values from 25μF to 75μF to find the value which will maximize the motor efficiency at a
In order to raise the starting torque, the single-phase induction motor of Problem 9.13 is to be converted to a capacitor-start, capacitor-run motor. Write a MATLAB script to find the minimum value
Consider the single-phase induction motor of Example 9.5 operating over the speed range 3350r/min to 3580r/min.a. Use MATLAB to plot the output power over the given speed range.b. Plot the efficiency
Consider the half-wave rectifier circuit of Figure a. The circuit is driven by a triangular voltage source Vs (t) of amplitude V0 = 9 V as shown in Fig. 10.50. Assuming the diode to be ideal and for
Repeat Problem 10.1 assuming the diode to have a fixed 0.6 V voltage drop when it is ON but to be otherwise ideal. In addition, calculate the time-averaged power dissipation in the diode.
Consider the half-wave SCR rectifier circuit of Figure supplied from the triangular voltage source of Figure. Assuming the SCR to be ideal, calculate the rms resistor voltage as a function of the
Consider the rectifier system of Example 10.5. Write a MATLAB script to plot the ripple voltage as a function of filter capacitance as the filter capacitance is varied over the range 3000μF < C
Consider the full-wave rectifier system of Figure with R = 500 fl and C = 200?F. Assume each diode to have a constant voltage drop of 0.7 V when it is ON but to be otherwise ideal. For a 220 V rms,
Consider the half-wave rectifier system of Figure. The voltage source is Vs (t) = V0 sin wt where V0 = 15 V, and the frequency is 100 Hz. For L = 1 mH and R = 1?, plot the inductor current iL (t) for
Repeat Problem 10.6, using MATLAB to plot the inductor current for the first 10 cycles following the switch closing at time t = 0.
Consider the half-wave rectifier system of Figure as L becomes sufficiently large such that co (L/R) >> 1, where co is the supply frequency. In this case, the inductor current will be
Consider the half-wave, phase-controlled rectifier system of Figure. This is essentially the same circuit as that of Problem 10.8 with the exception that diode D1 of Figure has been replaced by an

Showing 1500 - 1600 of 3459

First
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Last

Get In Touch

About Us
Contact Us
Career
Jobs
FAQ
Campus Ambassador

Company Info

Security
Copyrights
Privacy Policy
Terms & Condition
SolutionInn Fee
Scholarship

Services

Sitemap
Fun
Definitions
Become Tutor
Study Help Categories
Recent Questions
Expert Questions

Copyright © 2024 SolutionInn All Rights Reserved.

Get the SolutionInn - Study Help App