Motor Action:

Michael Faraday showed that passing a current through a wire freely suspended in a fixed magnetic field, a force that creates the conductor moving through the field causes. Conversely, if the conductor is not the magnet is then forced to create the magnet field will move in relation to the conductor.
Thus, in general, the force created by the current, now known as the Lorentz force between the conductors and the magnetic field or the magnetic field to create.
The size of the force on the conductor is given by:
F = BLI
Where F is the force on the ladder, L runs the length of the conductor and I the current through the conductor is
Generator Action:

Faraday also showed that the opposite is true - moving a conductor through a magnetic field or moving the magnetic field relative to the conductor, causing a current to flow into the pipe.
The size of the EMF is generated in this way, given by:
E = BLV
Where the generator emf E (or back EMF is in an engine) and v is the velocity of the conductor through the field

Alternative Motor Action (Interactive Fields):

Another form of motive power, which can not on the Lorentz force, and from the flow of an electric current, in principle, from the purely attractive (or repulsive) magnetic force which is exerted on a magnet or magnetically sensitive materials, as inferred be iron, if placed on the territory of another magnet. The movement of a compass needle in the presence of a magnet is an example. In practice, however, must create at least one magnet, the field of an electromagnet to achieve the necessary control of the magnetic field to the sustainable movement and at a practical level, the torque obtained.
Brushless DC motors and reluctance motors depends on this phenomenon as "reluctance torque", since no electric currents flow known in the rotor. Rotational movement is by sequential pulsing of the stator, a rotating magnetic field that drags along the moving-magnet with it will create.
For AC induction motors the rotating field is obtained by another method and the basic motor action depends on the Lorentz force, however, synchronous AC motors have magnet rotor elements are drawn to sync with the rotating field as in a brushless DC motor .

Reluctance torque:

Torque produced by the interaction of magnetic fields. Imagine a small bar magnet in the territory of another major magnet as the divide between the poles of a horseshoe magnet or the pole pair of an electric motor. (See chart reluctance motor). When the bar magnet with the poles of the great magnet focused its territory will be in line with the external field.

This is a state of equilibrium and the bar will not have any power to move it. However, if the bar is rotated out of alignment with the poles, either or moved, it is nevertheless a force once it moves into line with the external field. In the case of a lateral shift, it takes the power of the distance increases, but in case of a rotation will increase the force reaches a maximum when the bar is at right angles to the external field. In other words, the torque on the magnet is at a maximum when the fields are orthogonal and zero if the fields are aligned.
Salient poles Motors, which usually depend on the reluctance torque "salient poles - poles, which are outstanding. This is the river into sections focusing angle to maximize and focus the alignment of forces between the areas.
Torque of rotating fields For engines that depend on rotating fields, such as induction motors, brushless DC motors and restraint, the instantaneous torque depends on the rotor, from its angular position with respect to the angle of the flow wave. Although the flow wave tries to pull the rotor poles in line with the flow, there will always inertia and operating losses of the rotor back.
Slip:

The friction, windage and other losses cause the rotor of an induction motor at a slower speed than the rotating field which is associated to an angular misalignment between the rotating shaft and the rotational flow field with the rotor poles. The difference between the speed of the wave of the river and the speed of the rotor is called a "gaffe" and the torque of the motor is proportional to the slip.
Torque angle Even in the synchronous motors in which the rotor turns with the same speed as the flow wave, because of the aforementioned losses of the rotor poles will never achieve full alignment with the peaks in the flux wave, and there will be a shift between the rotating flux wave and the rotating field. Otherwise there would be no torque. This shift is called the "torque angle".

The torque of the motor is zero when the torque angle is zero and is at its maximum when the torque angle is 90 degrees. If the torque-angle exceeding 90 degrees, the rotor will pull out and stop synchronously.

Electrical machinery:

The majority of electrical machines (motors and generators) still sold today is based on the Lorentz force and its operations may be replaced by the following example, which turns a single-turn coil design electrical current in a magnetic field between the two poles, are shown a magnet. turn, several coils, the effective current NI (ampere turns), where N is the number of turns in the coil.
If the coil is supplied with a stream of machine that acts like a motor. If the coil is rotated mechanically, current is induced in the coil and thus the machine as a generator.

In rotating machines of the rotating element is called the rotor or armature and integral part of the stator is called.
Action and reaction In practice, both the engine and generator impact site at the same time.
Pass the effect of current through a conductor in a magnetic field that the line through the field, but once the conductor starts moving, it will create a generator to move a current through the pipe in the opposite direction to the current application. Thus, the movement of the head creates a "back EMF" which opposes the use of EMF.
Conversely, moving the ladder leads through the field to a current through the conductor which in turn exerts a force on the conductor applied force against the current.

The current flowing in the pipe, is given by:
I = (V - E)
R
Where V is the applied voltage, E is the back-EMF, and R is the resistance of the conductor.

Equilibrium operation under load To load the "action and reaction" effects described above an important automatic self-feedback mechanism in both DC and AC motors to adapt to changes in the application. As the engine load increases, it will tend to slow down, reducing the back EMF. This in turn allows more current to generate more torque to adapt to the increased load.

Magnetic Fields:

The motor of the magnetic field is made available through the stator and in the example above, the stator, a permanent magnet, but in the majority of electrical machines, the magnetic field by electromagnetic coils around the stator poles wound is provided. The stator windings are also in the field windings and the motor is said to be "illuminated box. The rotor is usually wrapped in an iron core to improve the efficiency of the magnetic circuit of the machine. Magnetic circuits In the case of electrical machinery, the magnetic circuit is the path of the magnetic flux through the stator body via the air gap, through the rotor and back through the air gap into the stator.

The length L of this path than the mean magnetic path length is known MMPI Magnetic circuits are designed to produce the maximum possible flow and concentrate it in the air gap between rotor and stator to move through the coils. The flux F measured in Webers The flux density B is measured in tesla and is as the magnetic flux F per unit area A. Thus defined, B = F / A, where A is the area through which the river flows.