What is a drill rule?

To someone who has chosen electrical engineering as their ownthe main profession, some of the basic properties of the electric current and the associated magnetic fields are very well known. One of the most important of these is the rule of the gimlet. On the one hand it is quite difficult to call this rule law. It is more correct to say that this is one of the fundamental properties of electromagnetism.

What is the drill rule? Definition though exists, but for a more complete understanding it is worth remembering the basics of electricity. As is known even from the school course of physics, the electric current is a movement of elementary particles carrying an electric charge over some conductive material. Usually, it is compared with the interatomic motion of valence electrons, which, due to an external action (for example, a magnetic pulse), receive an energy portion sufficient to leave their steady orbit in the atom. Let's conduct a mental experiment. For this we need the load, the source of the EMF and the conductor (wire), which connects all the elements into a single closed circuit.

The source creates a directionalthe motion of elementary particles. At the same time, as early as the 19th century, it was noticed that around such a conductor a magnetic field appeared that rotated in one direction or another. The rule of the borer can be used to determine the direction of rotation. The spatial configuration of the field is a kind of tube, in the center of which the conductor is located. It would seem: what a difference, how this generated magnetic field behaves! However, even Amper pointed out that two conductors with current act on each other with their magnetic fields, repelling or attracting each other, depending on the direction of rotation of their fields. Later on, based on a series of experiments, Ampere formulated and substantiated his law of interaction (by the way, he underlies the work of electric motors). Obviously, without knowing the rule of the borer, it is very difficult to understand what is happening.

In our example, the current direction is known - from"+" To "-". Knowing the direction makes it easy to use the rule of the drill. Mentally begin to twist gimlet standard right-hand thread in the conductor (along it) so that the resulting forward movement was coaxial with the direction of current flow. In this case, the rotation of the handle will coincide with the rotation of the magnetic field. You can use another example: screw the usual screw (bolt, screw).

This rule can be used a littleotherwise (although the main meaning is the same): if you mentally wrap your right hand with a current so that the four bent fingers indicate the direction in which the field rotates, then the bent thumb will indicate the direction of the current flowing through the conductor. Accordingly, the converse is also true: knowing the direction of the current, "wrapping" the wire, one can know the direction of the rotation vector of the created magnetic field. This rule is actively used in the calculation of inductors, in which, depending on the direction of the turns, it is possible to influence the flowing current (creating, if necessary, a counterflow).

The law of the mandrel allows us to formulateconsequence: if the right hand is placed in such a way that the lines of tension of the generated magnetic field enter into it, and four straightened fingers point to the known direction of motion of charged particles in the conductor, the thumb bent at 90 degrees will indicate the direction of the force vector exerting on conductor bias. By the way, this force creates a torque on the shaft of any electric motor.

As you can see, there are quite a lot of ways to use the above rule, therefore the main "difficulty" is the choice of each person to understand it.