Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Textbook Question
Chapter 3, Problem 19SQ
Select the best answer for each of the following.
The purpose of overload protection on a motor is to protect the
a. motor from sustained overcurrents.
b. wire from high currents.
c. motor from sustained overvoltage.
d. motor from short circuits.
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This question about control system
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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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- 9.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_forward3.) The time delay fuse using the strict standard rating for 2Ø, 230 V, 7.5 hp SCIM motor is A. 25 A B. 30 A C. 35 A D. Any of the abovearrow_forwardExplain how DOL magnetic starter works step by step with diagram and pictures.arrow_forward
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- 25.a. There are two wires labeled P1 and P2 at a DC motor's junction box. These wires will attach to whatinternal component of the motor?A. A speed potentiometerB. The parallel windingC. GroundD. A thermostat25.b. As you walk up to a machine, you see a technician tapping on the back section of a DC motor with alead mallet. This technician isA. cleaning the commutator.B. checking for end bell cracks.C. looking for weak or worn brushes.D. reseating the rear end bell on the case.arrow_forwardQ2] Fill in the blank (9 Marks) 1- The critical resistance of the D.C. generator is the resistance of 2- A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly volt. 3- The current drawn by a 120 V D.C. motor of armature resistance 0.5 2 and back e.m.f. 110 V is ampere. 4- The direction of rotation of a D.C. motor can be reversed by V2 VI 5- A 440V/110Vtransformer has 1000 turns on the primary winding. The number of turns on the secondary is 6- The main purpose of performing open circuit test on a transformer is to measure its 7-A 3-phase, 4-pole, 50 Hz induction motor runs at a speed of 1440 r.p.m. The rotating field produced by the rotor rotates at a speed of respect to the rotor. r.p.m. with 8- The advantages of skewing in induction motor are andarrow_forwardThe fuse in one of the supply phases of a running 3-phase I.M. blows off. Will the motor continue to run at ( i) original speed (ii) reduced speed (iii) come to stand still?arrow_forward
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