The basis of modern electrical engineering - the phenomenon of electromagnetic induction

The Phenomenon of electromagnetic induction in electrical engineering is one of the basic. It was empirically discovered in the distant 1831, English physicist Michael Faraday. At that time it was known that between a conductor and a magnet interact. It was believed that the fixed charges interact via an electric field and their movement (current) is manifested through a magnetic field. However, the prospect of practical use of this knowledge to the results of the experiment of Faraday was very vague. In fact, the scientist opening the phenomenon of electromagnetic induction, was the beginning of the foundations of modern electrical engineering.

The experience Itself was pretty simple: a bar of permanent magnet moved and was nominated into the Central space between the turns of the coil. The coil pins were connected to a sensitive device for measuring small values of current and voltage.

It Was observed that the motion of magnet galvanometer needle is deflected from the zero point. Moreover, the deviation was greater, the more intense the moving magnet. If you remember that it has two poles and the lines of field intensity, it becomes evident the relationship between the magnetic flux and creating an induction current.

Since the spontaneous current in the circuit can not occur, be made a logical conclusion about the appearance of the electromotive force (EMF), which in turn allows you to appear current. The law of electromagnetic induction Faraday suggests that the impact on the conductor a time-varying magnetic field causes a changing electric field and, in the presence of a closed circuit, current.

Recommended

"Knowledge is light and ignorance is darkness": the value, meaning and alternatives

There are some sayings that would seem to need no explanation, such as “teaching & ndash; light and ignorance – darkness”. But some still do not understand their meaning. But not only for such people is written by our article. I...

What was invented by Mendeleev for the army. The history and fate of the invention

D. I. Mendeleev was a brilliant Russian scientist-polymath, who made many important discoveries in various fields of science and technology. Many people know that he is the author of “Fundamentals of chemistry" and the periodic law of chem...

The origin of the Slavs. The influence of different cultures

Slavs (under this name), according to some researchers, appeared in the story only in 6 century ad. However, the language of nationality bears the archaic features of the Indo-European community. This, in turn, suggests that the origin of the Slavs h...

The Phenomenon of electromagnetic induction allowed the scientist to make a revolutionary conclusion: the cause of the electric field can be not only charges and changing magnetic field. In the future, they had formulated a generalization. Thus, Faraday's law for electromagnetic induction States: the emerging magnetic field EMF is in direct proportion to the rate of change of magnetic flux. The strength of the generated current for the closed loop is calculated according to Ohm's law.

The Phenomenon of electromagnetic induction is true not only for conductors but also for massive conductive bodies. So, a changing magnetic field creates in the thickness of the conductor (steel plate, etc.) eddy currents. They cause unwanted heating, so use various methods to eliminate them (in the transformers laminated plates of electrical steel). Note that in some instruments, the eddy currents are used (disc counters).

Soon after, in 1833, the physicist E. Lentz brought in the rule that the induced EMF creates a current of such direction to neutralize the cause. Example: changing magnetic field produces in the conductor a current. It is aimed so that its own magnetic field (it is present around the current-carrying conductors) counteracted the root cause.

The Phenomenon of electromagnetic induction enabled the development of electrical engineering to its present state. It is difficult to imagine a complete list of the equipment that uses it. For example, operation of generators in power plants based on this phenomenon. However, the construction of generating capacity has undergone significant changes since the time of Faraday, however, the General principle remains the same: lines of the magnetic field with high frequency is crossed by the conductive winding, with the result that electromotive force occurs and when there is a closed path that electric current. In addition to generators and motors, induction used in transformers.