Question

In: Physics

Describe the physics of an electric generator with relevant equations ?

Describe the physics of an electric generator with relevant equations ?

Solutions

Expert Solution

Electric generators are devices that convert mechanical energy to electrical energy. They induce an electromotive force (EMF) by rotating a coil in a magnetic field. It is a device that converts mechanical energy to electrical energy. A generator forces electric charge (usually carried by electrons) to flow through an external electrical circuit. Possible sources of mechanical energy include: a reciprocating or turbine steam engine , water falling through a turbine or waterwheel, an internal combustion engine, a wind turbine, a hand crank, compressed air, or any other source of mechanical energy. Generators supply almost all of the power for the electric power grids which provide most of the world's electric power.

Consider the setup shown in fig. Charges in the wires of the loop experience the magnetic force because they are moving in a magnetic field. Charges in the vertical wires experience forces parallel to the wire, causing currents. However, those in the top and bottom segments feel a force perpendicular to the wire; this force does not cause a current. We can thus find the induced EMF by considering only the side wires.Motional EMF is given to be EMF=B?v, where the velocity v is perpendicular to the magnetic field B (see our Atom on "Motional EMF"). Here, the velocity is at an angle ? with B, so that its component perpendicular to B is vsin?.

Diagram of an Electric Generator

A generator with a single rectangular coil rotated at constant angular velocity in a uniform magnetic field produces an emf that varies sinusoidally in time. Note the generator is similar to a motor, except the shaft is rotated to produce a current rather than the other way around.

Thus in this case the EMF induced on each side is EMF=B?vsin?, and they are in the same direction. The total EMF ? around the loop is then:

?=2Blvsin?.

This expression is valid, but it does not give EMF as a function of time. To find the time dependence of EMF, we assume the coil rotates at a constant angular velocity ?. The angle ? is related to angular velocity by ?=?t, so that:

?=2Blvsin?t.

Now, linear velocity v is related to angular velocity by v=r?. Here r=w/2, so that v=(w/2)?, and:

?=2Blw2?sin?t=(lw)B?sin?t.

Noting that the area of the loop is A=?w, and allowing for N loops, we find that:

?=NABw sin?t is the EMF induced in a generator coil of N turns and area A rotating at a constant angular velocity in a uniform magnetic field B.

Generators illustrated in this Atom look very much like the motors illustrated previously. This is not coincidental. In fact, a motor becomes a generator when its shaft rotates.

Attachment :

https://www.boundless.com/physics/textbooks/boundless-physics-textbook/induction-ac-circuits-and-electrical-technologies-22/magnetic-flux-induction-and-faraday-s-law-161/electric-generators-573-6256/


Related Solutions

Electric Generator Corporation The Electric Generator Corporation was founded in the early 1970s to develop and...
Electric Generator Corporation The Electric Generator Corporation was founded in the early 1970s to develop and market electrical products for industrial and commercial markets. Recently, the company has developed a new electric generator, the EGI, with a revolutionary design. Although its initial cost is $2,000 higher than any competing generator, reduced maintenance costs will offset the higher purchase price within 18 months. The Electric Generator sales force has been instructed to concentrate all effort on selling this new generator, as...
Electric field mapping Lab Physics 2212k 1) Describe the central electric field (E) shape in the...
Electric field mapping Lab Physics 2212k 1) Describe the central electric field (E) shape in the case of two parallel plates. 2) Do the distances between adjacent equipotential lines between the two parallel plates, approximately measure the same? Calculate an average value for the magnitude of the electric field between the plates. 3) Does the electric field extend beyond the edges of the plates in the two parallel plates experiment? 4) Is it possible for two different equipotential lines or...
Describe the photo electric event experimentally. Why can't the photoelectric phenomenon be explained by classical physics?
Describe the photo electric event experimentally. Why can't the photoelectric phenomenon be explained by classical physics?
Describe the extraction of magnesium from seawater in the Dow process. Show all relevant equations involved...
Describe the extraction of magnesium from seawater in the Dow process. Show all relevant equations involved in the process, starting with the precipitation of Mg2+ as Mg(OH)2(s) using CaO(s) until the electrolysis of molten MgCl2.
Which of the following statements are true regarding electric generators? Check all that apply. An electric generator creates...
Which of the following statements are true regarding electric generators? Check all that apply. An electric generator creates a time-dependent induced voltage. An electric generator is used to increase or decrease an alternating current voltage. An electric generator converts mechanical energy into electrical energy. An electric generator converts electrical energy into magnetic energy. An electric generator creates a time-independent induced voltage.
Describe the principle behind the working of a motor and the generator?Then, explain the “motor- generator...
Describe the principle behind the working of a motor and the generator?Then, explain the “motor- generator duality”
Explain with the diagram the structure and theory of the work of a three-phase electric generator,...
Explain with the diagram the structure and theory of the work of a three-phase electric generator, specifying the function of each part ؟؟
Share one physics equation that is relevant to a hand cannon(explain why)
Share one physics equation that is relevant to a hand cannon(explain why)
Write a reflection on Maxwell's Equations and how they relate to each other and physics as...
Write a reflection on Maxwell's Equations and how they relate to each other and physics as well as what they do. Give a break down to the equations as well as to how they relate to natural phenonmena
Discuss the operation of and resulting electric fields from the Van der Graaff generator. Include in...
Discuss the operation of and resulting electric fields from the Van der Graaff generator. Include in your answer an explanation of where the excess charge originates and how it is gathered to form a charge at the output. You should use diagrams to explain your answer and of the resulting electric field around the generator’s sphere.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT