Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Chapter 3, Problem 20SQ
To determine
Choose the best option that represents the consideration of number of magnetic starter poles.
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20.a. A capacitive sensor is used to detect the presence of _______ objects.A. ferrousB. nonmovingC. nonconductiveD. magnetic20.b. A three-phase motor can be made to run backwards byA. connecting a resistor in series with the armature.B. reversing the control voltage connections.C. reversing three of its power leads.D. reversing two of its power leads.
6.a. Arcing in manual starters is eliminated by the use ofA. overload relays.B. nonconductive contacts.C. blowout coils.D. spring-loaded handles.6.b. Chattering of AC contactors is prevented byA. blowout coils.B. air gaps.C. secondary windings.D. shading poles.
a)Please explain the connection methods of Current and Voltage Transformers?
b) Control the DC motor speed and direction. Draw the circuit.
Chapter 3 Solutions
Electric Motor Control
Ch. 3 - Prob. 1SQCh. 3 - How many poles are required on motor starters for...Ch. 3 - If a motor starter is installed according to...Ch. 3 - Using the time limit overload or the dashpot...Ch. 3 - What causes the AC hum or chatter in AC...Ch. 3 - What is the phase relationship between the flux in...Ch. 3 - In what AC and DC devices is the principle of the...Ch. 3 - What does the electrician look for to remedy the...Ch. 3 - What type of protective enclosure is most commonly...Ch. 3 - What advantage is there in using combination...
Ch. 3 - What safety feature does the combination starter...Ch. 3 - Prob. 12SQCh. 3 - How is the size of the overload heaters selected...Ch. 3 - What type of motor starter enclosure (include NEMA...Ch. 3 - Prob. 15SQCh. 3 - Prob. 16SQCh. 3 - Prob. 17SQCh. 3 - Prob. 18SQCh. 3 - Select the best answer for each of the following....Ch. 3 - Prob. 20SQCh. 3 - Prob. 21SQCh. 3 - Select the best answer for each of the following....Ch. 3 - Prob. 23SQCh. 3 - Select the best answer for each of the following....Ch. 3 - Select the best answer for each of the following....Ch. 3 - Select the best answer for each of the following....Ch. 3 - Select the best answer for each of the following....Ch. 3 - Prob. 28SQCh. 3 - Select the best answer for each of the following....Ch. 3 - Prob. 30SQCh. 3 - Prob. 31SQCh. 3 - What is the difference between a grounded control...Ch. 3 - A control transformer has a primary voltage of 480...
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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
- 1. It is a machine that converts mechanical energy to electrical energy. 2. It is a machine that converts electrical energy to mechanical energy. 3. It is cylindrical or drum-shaped where the coils are placed and can either be lap wounded or wave wounded. 4. It connects the commutator to the other parts of the DC machine. 5. It serves as the housing of the dc machine. 6. True or False: The shunt field winding is part of the armature. 7. True or False: The long shunt compound generator is when the armature is in series with the series field winding and parallel to the shunt field winding. 8-10. Your newly built house needs an elevator. Which from the following will be best to use- series, shunt or compound motor and why?arrow_forward9.a. The major failure area of a typical wound-field and wound-armature DC motor isA. a faulty commutator segment.B. open field windings.C. brush wear and failure.D. bearing failure.9.b. The magnetic material that's placed inside a coil of wire in a motor is called aA. concentrator.B. pole.C. form.D. rod.arrow_forward14.a. An encoder is a device that is used toA. excite the motor's interpoles.B. feed pack position information.C. reduce brush sparking.D. commutate the field windings.14.b. The letters CEMF are used to describeA. centrifugal forces within a motor.B. the portion of the supplied current that is converted to heat.C. countervoltages and currents created within a motor.D. critical winding currents that should not be exceeded.arrow_forward
- Identify the DC Generator used for Arc welding purpose. With a neat sketch explain its working. list its advantages & disadvantages??arrow_forwardThe preferred method for applying the field excitation voltage uses a field relay which operates on the principle of A. speed application. B. time application.C. angle application. D. thermal application.arrow_forwardWhile discussing armature testing: Technician A says to test for shorts, place the ohmmeter leads on a commutator segment and armature shaft. Technician B says that continuity should exist between the commutator and the armature shaft. Who is correct?arrow_forward
- List the probable causes if the armature dos notable release after the magnetic starter is de - energized .arrow_forwardQuestion 11 Design a Duplex layer simplex lap winding DC machine armature winding by providing a complete wiring diagram with the following Number of Poles: 2 Number of Slots; 8 Thank you and Godbless ASAP pleaseearrow_forwardExplain how DOL magnetic starter works step by step with diagram and pictures.arrow_forward
- Industrial Motor Controls 8.a. A typical motor speed control circuit that is controlled by an analog current loop will have a current ofA. 4-20 mA.B. 2-20 mA.C. 5-50 mA.D. 0-10 mA.8.b. Which one of the following statements is true of a disabled contact or coil?A. The disabled element has been automatically disabled due to module failure.B. The disabled element is held false by the PLC.C. A disabled contact or coil is caused by a faulty memory location in the PLC.D. A contact must be in the disabled state before it can be forced ON or OFF.arrow_forwardQ51 Which NEC table is used to determine the full-load current of a torque motor? Select one: A. NEC TABLE 430.6(B) B. NEC TABLE 430.7(B) C. NEC TABLE 430.24 D. NEC TABLE 430.22arrow_forward5-What is the use of auxiliary contact in the magnetic controller?arrow_forward
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