Engineering Talks Open Club  ·  30 members ### Category

Engineering Subjects

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1. What's new in this club
2. Power factor is the cosine of the angle between the voltage and the current. It is the third factor in the product that expresses the power, P = V*I*cos(phi) where phi is the phase angle. DrD
3. Real power is just what it says, power as in work done per unit of time. In electrical systems, the real power is calculated as Preal = V*I*cos(phi) where V = voltage I = current phi = phase angle between current and voltage Reactive power is Preact = V*I*sin(phi) I've never heard the term "apparent power" but I suspect what you mean is what I know as Volt-Amperes = V*I The real power is the in-phase part of the volt-ampere product while the reactive power is the out-of-phase part of that product. DrD
4. Ths is done to reduce eddy current losses by preventing current flow perpendicular to the laminations. The laminates are electrically insulated from each other (usually by varnish) which blocks current flow while allowing magnetic flux to flow freely. DrD
5. This process is called "field weakening" and it was used for speed control on the ancient rolling mill where I worked long ago. As the field current is reduced, flux must be cut more rapidly to maintain the back EMF. The only way this can happen is for the rotor to turn more rapidly, thereby cutting more flux per unit of time. DrD The term "linear machine" seems ambiguous to me. I think you intend to describe an electrical machine (motor) described by linear differential equations. The term can also be used to describe an electric motor for which the moving element translates rather than rotates. For a translating induction machine, the usual acronym is LIM, Linear Induction Machine. Such machines can also be built in synchronous form, known as LSM, Linear Synchronous Machines. The linear machines of this sort are being used to launch aircraft from aircraft carriers. DrD
6. Now that is an interesting question! Do you mean Ampere's circuital law? or Do you mean Ampere's force law?
7. What is power factor? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
8. What are real, reactive, and apparent power? What units are they measured in? How are they related? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
9. Will current be leading or lagging voltage in an inductive load? Will the reactive power of the load be positive or negative? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
10. Just how does a decrease in flux produce an increase in speed in a linear machine? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
11. ## The linear machine in Figure 1-19 is running at steady state. What would happen to the bar if the voltage in the battery were increased?

The linear machine in Figure 1-19 is running at steady state. What would happen to the bar if the voltage in the battery were increased? Explain in detail. You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
12. Why is the linear machine a good example of the behavior observed in real de machines? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
13. What conditions are necessary for a magnetic field to produce a voltage in a wire? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
14. What conditions are necessary for a magnetic field to produce a force on a wire? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
15. What is Faraday's law? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
16. Why are all cores exposed to ac flux variations laminated? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
17. What are eddy current losses? What can be done to minimize eddy current losses in a core? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
18. What is hysteresis? Explain hysteresis in terms of magnetic domain theory. You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
19. ## How does the relative permeability of a ferromagnetic material vary with magneto motive force?

How does the relative permeability of a ferromagnetic material vary with magneto motive force? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
20. What is a ferromagnetic material? Why is the permeability of ferromagnetic materials so high? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
21. What is reluctance? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
22. ## How does the magnetic circuit concept aid in the design of transformer and machine cores?

How does the magnetic circuit concept aid in the design of transformer and machine cores? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
23. What is magnetizing intensity? What is magnetic flux density? How are they related? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
24. What is Ampere's law? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
25. What is torque? What role does torque play in the rotational motion of machines? You can write the answer and upload releva﻿nt images to justif﻿y the answer (if required) Let's together discuss and contribute﻿ in ﻿making the best answ﻿﻿﻿﻿﻿﻿e﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿r
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