Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 3, Problem 25SQ
Select the best answer for each of the following.
The thermal relay heating element is selected
- a. 15 percent under voltage.
- b. 10 percent over voltage.
- c. from the motor’s FLA and a manufacturer’s selection chart.
- d. by ambient temperature.
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
Air- cold condensers use? To drive air across the condensing coil. A. ambient evaporation b. A pump c. A temperature-difference fan d. A motor--driven fan
a)Please explain the connection methods of Current and Voltage Transformers?
b) Control the DC motor speed and direction. Draw the circuit.
A three-terminal manual starting rheostat has a resistance of 5.2 ohms in its starting resistor. The holding coil resistance is 10 ohms. This starting rheostat is connected to a shunt motor. The resistance of the armature is 0.22 ohm; the resistance of the shunt field is 100 ohms. The line voltage is 220VDC.
a. What is the starting surge current taken by the motor?
b. What is the current in the holding coil with the moveablew arm in the run position?
c. What is the CEMF with the movable arm in the on position if the armature current is 20 amps?
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...
Knowledge Booster
Learn more about
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
- 22.a. One common type of electronic circuit component that is used to control the voltage and current to aDC motor is theA. silicon-controlled rectifier.B. resistor.C. capacitor.D. diode.22.b. Which one of the following types of motors can be powered with either AC or DC electricity?A. Servo motorB. Pancake motorC. Universal motorD. Shunt-wound motorarrow_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_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_forward
- Can you please illustrate in diagram and explain on how to do the Conductance Test of the Motor Control Center Bus Bar. How much the acceptable torence value of the results.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_forwardQUESTION 12 The proper way to determine the required over-current protection is to: determine the FLA based on the nameplate. Use the standard rule of thumb that the over-current protection shall be 7 to 10x the locked rotor amps. determine the watts by converting the HP rating on the nameplate to watts. to determine the FLC by looking up the value in the appropriate table(s) in the NEC as they relate to the horsepower of the motor.arrow_forward
- A step up chopper has an input of 200 volts and output of 250 volts. The blocking period is each cycle is 0.6x10-3 seconds. Find the period of conduction in each cycle and frequency of operation?arrow_forward20.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_forward1. 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_forward
- a. Draw the schematic diagram for the variable reluctance sensors. (" b. Explain the operation of the variable reluctance sensors.( c. List out any two advantages of bourdon tube.(*arrow_forwardThis question about control system I need the answer about half an hourarrow_forward6.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.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Electricity for Refrigeration, Heating, and Air C...Mechanical EngineeringISBN:9781337399128Author:Russell E. SmithPublisher:Cengage Learning
Electricity for Refrigeration, Heating, and Air C...
Mechanical Engineering
ISBN:9781337399128
Author:Russell E. Smith
Publisher:Cengage Learning
What is an electric furnace and how does it work?; Author: Fire & Ice Heating and Air Conditioning Inc;https://www.youtube.com/watch?v=wjAWecPGi0M;License: Standard Youtube License