In 1820, the eminent French physicist Andre Marie Ampere (which is named in his honor the unit of measurement of electrical current) formulated one of the basic laws of electrical engineering throughout.Later this law was fixed for the name of the power amp.
As is known, during the passage of electric current in the conductor occurs around its own (secondary) magnetic field intensity lines which form a kind of the rotating shell.The direction of these magnetic flux lines is determined by the right hand rule (the second name of "right-hand rule"): mentally bow with his right hand conductor so that for charged particles coincides with the direction indicated by the thumb bent.As a result, the other four fingers, clasping wire, point to the rotation of the field.
If you place these two parallel conductors (thin wire), then on the interaction of magnetic fields will affect the power amp.Depending on the direction of the current in each conductor, they can be attracted or repelled.At currents flowing in the same direction, the force exerted on them amperes attracting action.Accordingly, the opposite direction of the currents causes repulsion.This is not surprising: while like charges repel, in this example, do not interact with the charges and magnetic fields.Since the direction of rotation is the same, the final field is the vector sum rather than difference.
other words, the magnetic field in a certain way affects the conductor that crosses the line tension.Ampere force (an arbitrary form of the conductor) is determined from the formula of the law:
dF = B * I * L * sin a;
where - I - the value of current in the conductor;B - magnetic induction, which houses the current conductive material;L - up to calculate the length of the conductor with the current (and in this case it is assumed that the conductor length and strength tend to zero);alpha (a) - vector angle between the direction of motion of the charged particle and the lines of the external field.Corollary follows: when the angle between the vectors is 90 degrees it sin = 1 and the maximum value of the force.
vector direction of the force amp is determined by the rules of his left hand: mentally place the palm of his left hand so that the lines (vectors) of the magnetic induction of the external field were in open palm, while the other four straightened thumb indicates the direction in which the moving currentExplorer.Then the thumb bent at an angle of 90 degrees, show the direction of force acting on the conductor.If the angle between the electric current and an arbitrary line of the induction is too small, to simplify the application of the rules must go hand in not the induction vector, and the module.
use of force made it possible to create an amp electric.We are all accustomed to the fact that it is sufficient to flip the switch electric appliance equipped with an engine that its actuator come into effect.And about the processes occurring at the same time, no one much minds.The direction of the Ampere force not only explains the principle of operation of the engines, but also to determine where it will be sent to the torque.
For example, imagine a DC motor, his anchor - a frame-basis with a winding.An external magnetic field is produced by special poles.Since the coil wound on the armature, circular, then its opposite sides of the direction of current in the conductor sections of the counter.Consequently, the vector of the force ampere counterclaims.Since the armature is fixed to the bearings, the mutual action of the force vectors amp creates torque.With the growth of the current value of the current increases and power.That is why the rated electric current (specified in the certificate for electrical equipment) and torque directly linked.Increasing the current limited design features: section used for winding wire, number of coils and others.
