EBK ELECTRIC MOTOR CONTROL
10th Edition
ISBN: 9780100784598
Author: Herman
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
thumb_up100%
Chapter 8, Problem 1SQ
To determine
Explain why contactors are described as control pilot devices and large magnetic switches.
Expert Solution & Answer
Explanation of Solution
Discussion:
Contactors are electromagnetic switches that are very convenient for interrupting and connecting the branch circuits based on the range or size of contractors.
Contactors with a combination of pilot devices are used to control AC motors, switch lightning, and heavy loads.
Small range contactors with a combination of control devices are used for larger controls. Large contactors can control the heavy currents where overload protection is provided separately. Relays might be used to control the large contactors.
Conclusion:
Thus, the reason why contactors are described as control pilot devices and large magnetic switches is explained.
Want to see more full solutions like this?
Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
A three-phase transmission line supplies power to three loads at a voltage
408 Vrms (line to line). The loads are as follows:
Load 1:
S₁ = 100+ j50 VA
Load 2:
S₂ = 40-j20 VA
Load 3:
S3 = 10 + j0 VA
Find the magnitude of the line current | Line and the combined power factor of
the loads.
Hint:
Steral \= √3 | Vime |× | Ime |
line
line
Can you show why the answer to this question R = 199 ohm?
2.5. Find the half-power beamwidth (HPBW) and first-null beamwidth (FNBW), in radians and degrees, for the following normalized radiation intensities: (a) U(9) cos θ cos(20) (b) U(θ)-cos2 θ cos2(26) (c) U(θ) = cos(θ) cos(30) (0 < θ < 900,0 < φ 360) (d) U(t) = cos2(9) cos2(39) (e) U(9) = cos(29) cos(39) (f) U (ecos (20) cos (30)
Chapter 8 Solutions
EBK ELECTRIC MOTOR CONTROL
Ch. 8 - Prob. 1SQCh. 8 - What is the principal difference between a...Ch. 8 - What causes the arc to move upward in a blowout...Ch. 8 - Why is it desirable to extinguish the arc as...Ch. 8 - Prob. 5SQCh. 8 - Why will the blowout coil also operate on AC?Ch. 8 - Prob. 7SQCh. 8 - Are ON control stations used in multiple locations...
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
- Don't use ai to answer I will report you answerarrow_forwardDon't use ai to answer I will report you answerarrow_forwardA 60 Hz, 230 kV, 275 km long, uncompensated three-phase transmission line consists of three conductors bundled by phase, such that each conductor in the line is of the ACSR Falcon type. The separation between each bundled conductor is d = 45 cm and the separation between each phase of the line is 2.4 m. Calculate: "The parameters R, L, C of the line in Q2/km; µH/m and nF/m. And the total values of ZL and YC in Q and S, respectively, and in polar coordinates." Generalized constants A, B, C and D of the line, according to the type of transmission line. Present the results in rectangular coordinates. If a three-phase wye load draws 3/4 of the nominal current of the 300 MW system with FP = 0.85 lagging and at 230 kV, calculate: (a) Current at the load in KA (b) Voltage at the source in KV, (c) Current at the source in kA and (d) power at the source in MVA. Obtain the results per phase. Transmission line voltage regulation percentagearrow_forward
- Determine the required EMT size for the following combination of conductors:18. Four 8 AWG Type THW and four 12 AWG Type THW:19. Three 350 kcmil and one 250 kcmil Type XHHW conductors and a 4 AWG bare conductor:20. In a nonmetallic-sheathed (Type NM) cable installation, a 10⁄3 with equipmentgrounding conductor is installed in a metal octagonal box to supply two 12⁄2 withequipment grounding conductor branch-circuit cables. What is the minimum sizebox? The box contains internal cable clampsarrow_forwardFor problems 8 and 9, determine the correct box size for each of the following conditions:8. Two nonmetallic sheathed cables with two 12 AWG conductors, an equipment groundingconductor, and a switch in a metal box without a plaster ring.9. A raceway run serving a series of luminaires, connected to a total of three circuits. Theluminaires are supplied by 120 volts from a 3-phase, 4-wire system. Each box will containtwo circuits running through the box and a third circuit connected to a luminaire, which issupported by a luminaire stud in the box. Use 12 AWG Type THHN conductors.arrow_forward28. The minimum size raceway for the following conductors is: a. Three, 250 kcmil conductors with XHHW insulation b. One, 3⁄0 AWG conductor with XHHW insulation c. One, 4 AWG conductor with XHHW insulation29. The minimum size raceway for the following conductors is: a. Twelve, 6 AWG conductors with THHN insulation b. Nine, 8 AWG conductors with THHN insulation c. Eighteen, 10 AWG conductor with THHN insulation d. One, 10 AWG equipment grounding conductor with THHN insulation30. The minimum size wireway for the following with parallel conductors is: a. Two sets of three, 250 kcmil conductors with XHHW insulation b. Two, 3⁄0 AWG conductors with XHHW insulation c. 1, 4 AWG conductor with XHHW insulation d. The conductors terminate on three power distribution blocks. Each one has adimension of 4 in. wide and 3 in. high:arrow_forward
- box fill calculationsarrow_forwardTwo trade size 3 raceways enter a pull box directly across from each other. No other raceways enter the box. What are the minimum dimensions of the box?11. Length ______________________12. Width ______________________13. Depth ______________________Two trade size 3 raceways enter a pull box at right angles to each other. No other racewaysenter the box. What are the minimum dimensions of the box?14. Length ______________________15. Width ______________________16. Depth ______________________arrow_forwardnot use ai pleasearrow_forward
- For Questions 21, 22, and 23, two 3-in. raceways enter a pull box, one through a side and theother in the back. Four 500 kcmil, type THHN conductors will be installed in the raceway.No other raceways enter the box. What are the minimum dimensions of the pull box 21. Length ________________22. Width ________________23. Depth ________________arrow_forwardFor Questions 24, 25, 26, and 27, determine the answers using the information shown in the drawing. Trade size 2 conduit Trade size 2 conduit Trade size 3 conduit Trade size 3 conduit Trade size 2 conduit Trade size 2 conduit 24. Dimension a must be at least. 25. Dimension b must be at least the same conductors). inches. inches (the raceways contain inches. 26. Dimension c must be at least 27. Do you foresee any difficulties in installing the conductors in these raceways? Explain.arrow_forwardFor problems 1-4, select from the following list of raceway types. Check the letter(s) representing the correct response(s): a. electrical metallic tubing b. electrical nonmetallic tubing c. flexible metallic tubing d. rigid metal conduit e. intermediate metal conduit f. rigid nonmetallic conduit 1. Which raceway(s) may be used where cinder fill is present? ☐ a. ☐ b. ☐ c. ☐ d. ☐ e. 2. Which raceway(s) may be used in hazardous locations? ☐ a. b. ☐ c. ☐ d. 3. Which raceway(s) may be used in wet locations? ☐ a. ☐ b. ☐ c. ☐ d. ☐e. ☐ ☐ e. ☐ f. ☐ d. ☐ e. ☐ f. 4. Which raceway(s) may be used for service entrances? ☐ c. ☐ a. O b.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
Delmar's Standard Textbook Of ElectricityElectrical EngineeringISBN:9781337900348Author:Stephen L. HermanPublisher:Cengage Learning
Electricity for Refrigeration, Heating, and Air C...
Mechanical Engineering
ISBN:9781337399128
Author:Russell E. Smith
Publisher:Cengage Learning
Delmar's Standard Textbook Of Electricity
Electrical Engineering
ISBN:9781337900348
Author:Stephen L. Herman
Publisher:Cengage Learning