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 4, Problem 15RQ
A three-phase motor nameplate indicates a full load current of 362 amperes. The nameplate indicates that the heaters are to be sized for 125% of motor full load current. Current transformers with a ratio of 600:5 are used to reduce the motor current. Using the chart shown in Figure 4–7B, determine the size of overload heaters needed to protect this motor.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
5. The operation factor of a unit is 80% and its use factor is 50%. If the load factor and reserve-over-peak are 42% and 3000 kW,
respectively, the average load is
kW.
You are Working as a plant electrician. You were told that a large DC motor was returned from the rewind shop and was installed on the previous shift. The motor seem to operate properly until the load was added. The motor then stopped, reversed direction, and begun to run at high speed. What is the probable cause of the trouble, and what would you do to correct the problem? Explain your answer.
10. The output voltage of a turbine is 224 V at no load and 218 V at full load.
How much is the copper loss in the transformer if the current is 1000 A
at full load, assuming that the entire copper loss materializes inside the
transformer?
Chapter 4 Solutions
Understanding Motor Controls
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
- A 480-volt three-phase load is rated at 34.5 kVA. It is to be supplied with variable three-phase voltage. Because the load is continuous, the transformers ratings are to be increased by 1.25% of the rated load. Three variable autotransformers are used to supply this load. Refer to Table 4-2 and determine the standard size of each transformer that should be used to make this connection.arrow_forwardA large motor has a full load current rating of 425 amperes. Current transformers with a ratio of 600:5 are used to reduce the current to the overload heaters. What should be the full load current rating of the overload heaters?arrow_forwardName three factors that determine the amount of induced voltage.arrow_forward
- Power-consuming devices are wired in _____(series orparallel).arrow_forwardRefer to the transformer shown in Figure 5-13 to answer the following questions. The transformer shown in Figure 5-13 is supplying 325 volt amperes to a load. The primary voltage is 240 volts. What is the primary current? Figure 5-13 Autotransformer practice problems.arrow_forwardIf the load in question 7 is connected in a wye, what would be the line voltage and line current supplying the load?arrow_forward
- Refer to the transformer shown in Figure 5-13 to answer the following questions. What is the turns ratio of the winding between points B and E as compared to the winding between points D and E? Figure 5-13 Autotransformer practice problems.arrow_forwardIf the load in question 7 was supplied by two autotransformers connected in open delta, what would be the minimum standard size transformers that could be used to supply this load?arrow_forwardTwo transformers rated at 100 kVA each are connected in an open-delta connection. What is the total output power that can be supplied by this bank?arrow_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
Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher: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
Refrigeration and Air Conditioning Technology (Mi...
Mechanical Engineering
ISBN:9781305578296
Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson
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