Understanding Motor Controls
4th Edition
ISBN: 9781337798686
Author: Stephen L. Herman
Publisher: Delmar Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 26, Problem 1RQ
Name two requirements that must be met before a motor can be used for wye-delta starting.
Expert Solution & Answer
To determine
Identify two requirements for a motor to be used with wye-delta starting.
Explanation of Solution
Wye-delta starting is used to reduce the inrush current and the starting torque. The two requirements for a motor to be used with wye-delta starting are:
- The design of the motor must be such that the stator winding is connected in delta during the running time.
- All the leads of the stator windings must be accessible.
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
State four advantages of a pre-engaged starter when compared with an inertia type.
A 50 Hz pump drive requires a torque of 70 Nm approx. at 1450 rpm approx. for 1 minute followed by 5 minutes running
unloaded. This cyclic pattern is repeated continuously. The motor is to be selected from a range of general-purpose motors
with continuous ratings of 2.2, 3, 4, 5.5, 7.5, 11, 15 and 20 kW. The motors have a pull-out torque of 200%.
1.
Select the pole number.
2.
Calculate the continuous power rating.
3.
4.
Calculate the required power rating given the pull out torque rating.
Estimate the slip when the motor drives the pump at the required speed.
Choose the motor from the range of options that is most fit for purpose.
5.
Enter your answers in the units indicated (without unit symbols) corrected if necessary to two decimal places.
Answer:
Number of poles=
✓
Continuous power rating (kW)=
Required power rating for 200% pull out torque (kW)=
Percentage slip (%) =
Most suitable motor from given range (kW)-
4. Describe two type of starting system principles and draw
the basic starting circuit
Chapter 26 Solutions
Understanding Motor Controls
Ch. 26 - Name two requirements that must be met before a...Ch. 26 - Prob. 2RQCh. 26 - Prob. 3RQCh. 26 - Refer to the circuit shown in Figure 26–9. Assume...Ch. 26 - Refer to the circuit shown in Figure 269. Assume...Ch. 26 - Prob. 6RQCh. 26 - The motor nameplate of a wye-delta started motor...Ch. 26 - Prob. 8RQCh. 26 - Refer to the circuit shown in Figure 2614. What is...Ch. 26 - Refer to the circuit shown in Figure 2614. When...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- TO THE NEXT PROBLEM Design a complete belt drive system for an AC motor (NT) running a fan 12 hrs/day, with an input power 10 hp and input speed of 1000 RPM. The desired output RPM and center distances are 500 RPM and 36 inch, respectivelyarrow_forwardRefer to the schematic diagram in Figure 318. Assume that the motor is not running. When the third speed push button is pressed, the motor starts in its lowest speed. After a delay of 3 seconds, the motor accelerates to second speed and 3 seconds later to third speed. After a period of about 1 minute, the fourth speed push button is pressed, but the motor does not accelerate to fourth speed. Which of the following could cause this problem? a. Control relay CR2 coil is open. b. S2 contactor coil is open. c. CR3 coil is shorted. d. S3 contactor coil is open.arrow_forwardRefer to Figure 21–1 to answer the following questions. Assume that HOA SW 120 has been set in the auto position. List four ways by which coil CR-8 could be energized.arrow_forward
- Select the proper choice(s) for each of the following statements: 1) To control single-acting cylinder we just need: double-acting cylinder we should use A2/2-way, 5/2-way, (C) 3/3-way, 3/4-way, 2) In DCV. (B) 3/2-way, 4/2-way, (D) 4/3-way, 3/2-way. mid poistion of DCV, we can move cylinder piston rod freely without resistance by hand. (A) working ports are exhausted, (C) working ports are pressurized, 3) In pneumatics we use A Compressor (B) Pump, DCV, while to control the 4) Quick exhaust valve is used to (A) increase the cylinder return speed. (C) meter-out the cylinder speed (B) all ports are closed. no one of these options. to obtain high pressure air. (C) Turbine, (D) pressure relief valve. (B) meter-in the cylinder speed, (D) increase the cylinder extending speed. 6) Meter-in of cylinder movement is used to control the Afluid that enters the hydraulic cylinder, (B) fluid that exits the hydraulic cylinder, (C) fluid that enters the DCV (D) fluid that exits the DCV. 5) One of the…arrow_forwardWhat is the most common NEMA design code found on squirrel- cagetype motors?arrow_forwardASAParrow_forward
- To what is countertorque proportional?arrow_forwardThe reversing motor,which is controlled by two power relays,can be rotated in both directions as shown in the figure beiow.When the motor is mechanically combined with a lead screw,the rotary motion is converted to a linear one,such as the one moving lef tor right on the worktable in the layout.The desired direction of rotation is selected via the two STAFIT buttons,respectively.The limit switches LS1 and LS2,located at the two extreme motion limits,ensure 1-rqtf we forget to stop the movement of the worktable,then it will stop automatically, and the mechanism of the layout will not be destroyed.Draw the circuit of automation.arrow_forwardDefine relayarrow_forward
- 17- The memory unit of PLC is used to write the program to control output device. Select one: True Falsearrow_forwardWhy are SCRs used to construct a bridge rectifier in many solid-state variable frequency drives?arrow_forwardThe device that prevents the engine from turning the armature of the starter motor is the. overrunning clutch pinion gear flywheel pole shoearrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Understanding Motor ControlsMechanical EngineeringISBN:9781337798686Author:Stephen L. HermanPublisher:Delmar Cengage Learning
Electrical Transformers and Rotating MachinesMechanical EngineeringISBN:9781305494817Author:Stephen L. HermanPublisher:Cengage Learning
Automotive Technology: A Systems Approach (MindTa...Mechanical EngineeringISBN:9781133612315Author:Jack Erjavec, Rob ThompsonPublisher:Cengage Learning
Understanding Motor Controls
Mechanical Engineering
ISBN:9781337798686
Author:Stephen L. Herman
Publisher:Delmar Cengage Learning
Electrical Transformers and Rotating Machines
Mechanical Engineering
ISBN:9781305494817
Author:Stephen L. Herman
Publisher:Cengage Learning
Automotive Technology: A Systems Approach (MindTa...
Mechanical Engineering
ISBN:9781133612315
Author:Jack Erjavec, Rob Thompson
Publisher:Cengage Learning
Mechanical Design (Machine Design) Clutches, Brakes and Flywheels Intro (S20 ME470 Class 15); Author: Professor Ted Diehl;https://www.youtube.com/watch?v=eMvbePrsT34;License: Standard Youtube License