Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Chapter 3, Problem 16SQ
To determine
Choose the best option that represents the action of the contacts when the magnetic coil of the starter is de-energized.
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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?
6.a. When you're taking a PM motor apart you should exercise special care not to damage theA. end bells.B. commutator.C. permanent magnets.D. brush holders.6.b. A PM field servo motor may be equipped with a resolver that is used toA. excite the armature windings.B. create a voltage that increases with velocity.C. prevent the brushes from sparking.D. feed back position information.
Explain how DOL magnetic starter works step by step with diagram and pictures.
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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- 1. Explain the working Principle of Single Phase Induction Motor. 2. What are the different types of Starters to control AC-Motor. Explain briefly. 3. Explain DOL starter of Single Phase Induction Motor briefly. 4. What is the purpose of the magnetic contactor? 5. What is the use of auxiliary contact in the magnetic controller? 6. What happens when the holding coil gets the supply in the magnetic controller? 7. Explain the working principle of a relay.arrow_forward23. When the circuit breaker is always tripping, most likely There is an overloading c. The supply line are open a. b. There is an over current d. The load is removed 24. The synchronous motor is not inherently self- starting because the rotating magnetic field does not have enough poles b. the rotating magnetic field is produced by only 50 HZ frequency currents the force required to accelerate the rotor is to the synchronous speed in an instant is d. the starting devices to accelerate the rotor to near synchronous speed is absent 25. Synchronous motor has speed a. slight drop in speed on full load b.high speed at low torque а. с. c. constant speed d. low speed at high -arrow_forwardIf a centrifugal switch assembly in a split-phase or capacitor motor fails, you'll most likely have a A. slowly turning motor.B. loudly humming motor.C. motor turning at too high a speed. D. motor that has reversed direction while running.arrow_forward
- list the probable causes if the armature does not release after the magnetic starter is de-energized?arrow_forwardList the probable causes if the armature dos notable release after the magnetic starter is de - energized .arrow_forwardc) Based on Figure 3 (c), a basic DOL starter induction motor at a power station is experiencing run-time error and unable to start, based on your understanding, interpret the sequence of troubleshooting shall be carried out to identify the root cause of the abnormalities. 3P 1P MCB MCB STOP K1 START MOTOR Figure 3 (c)arrow_forward
- 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.arrow_forward5. Which part (s) of the DC motor connect the power supply to the split- ring and coil? * O a) Carbon brushes O b) Magnets O c) Commutator d) Slip ringsarrow_forward4.a. The device which responds to the heat developed within the motor is theA. shading coil.B. short-circuiter.C. bimetallic protector.D. current-operated relay.4.b. How is a rotating magnetic field produced during starting in a split-phase motor?A. A capacitor is inserted in the auxiliary-winding circuit.B. A low resistance coil is placed around a portion of each pole.C. Brushes are shifted off the hard-neutral position.D. An auxiliary winding is made with a high ratio of resistance to reactance.arrow_forward
- 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.arrow_forwardExplain the characteristics and how the following motor starters work. 1.Slip Ring a. Variable Resistance b. Fixed Starting Resistancearrow_forwardQ3/ Chose the correct answer for the following 1. Synchronous motors are generally not self-starting because (a) the direction of rotation is not fixed (b) the direction of instantaneous torque reverses after half cycle (c) startes cannot be used on these machines (d) starting winding is not provided on the machines 2. The power developed by a synchronous motor will be maximum when the load angle is (a) Zero (b) 45° (c) 90° (d) 120° 3. An over-excited synchronous motor takes (a) leading current (b) lagging current (c) both (a) and (b) (d) none of the above 4. In a synchronous motor, the magnitude of stator back e.m.f. £& depends on (a) d.c. excitation only (b) speed of the motor (c) load on the motor (d) both the speed and rotor flux 5. A pony motor is basically a (a) small induction motor (c) D.C. shunt motor (b) D.C. series motor (d) double winding A.C./D.C. motorarrow_forward
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