3 phase induction motor

 

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The principle of AC motors is based on the use of a rotating magnetic field produced by alternating voltages. The circulation of a current I in a coil creates a magnetic field B (see Fig. 1).
This field is carried by the axis of the coil, its direction and its intensity depend on the current I.
If thiscurrent is alternating, the field varies in direction and direction at the same frequency of the current.
If two coils are placed close to each other, the resulting field is the vector sum of the two fields.
In the case of a three-phase motor, the coils are placed in the stator at 120 ° to each other, three fields are thus created.
Given the nature of the three-phase current, the three fields are out of phase.
 Field resulting magnetic spins at the same frequency as the current,
i.e. 50tr / s.