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The rotating magnetic field is the key principle in the operation of induction machines.The induction motor consists of a stator and rotor.In the stator a group of fixed windings are so arranged that a two phase current, for example, produces a magnetic field which rotates at an angular velocity determined by the frequency of the alternating current.
In synchronous motors, the stator carries 3 phase currents and produces 3 phase rotating magnetic flux (and therefore a rotating magnetic field). The rotor eventually locks in with the rotating magnetic field and rotates along with it. Once the rotor field locks in with the rotating magnetic field, the motor is said to be synched.
A three-phase power supply provides a rotating magnetic field in an induction motor. Inherent slip – unequal rotation frequency of stator field and the rotor. In both induction and synchronous motors, the AC power supplied to the motor's stator creates a magnetic field that rotates in synchronism with the AC oscillations. Whereas a ...
If the rotor terminals are connected to a three-phase electric power network, a rotating magnetic field will be driven into the magnetic core. The resulting flux will produce an emf on the windings of the stator with the particularity that if rotor and stator are physically shifted by an angle α, then the electric phase shifting of both ...
In a three-phase induction machine, alternating current supplied to the stator windings energizes it to create a rotating magnetic flux. [11] The flux generates a magnetic field in the air gap between the stator and the rotor and induces a voltage which produces current through the rotor bars. The rotor circuit is shorted and current flows in ...
In vector control, an AC induction or synchronous motor is controlled under all operating conditions like a separately excited DC motor. [21] That is, the AC motor behaves like a DC motor in which the field flux linkage and armature flux linkage created by the respective field and armature (or torque component) currents are orthogonally aligned such that, when torque is controlled, the field ...
If connections to the rotor coils of a three-phase motor are taken out on slip-rings and fed a separate field current to create a continuous magnetic field (or if the rotor consists of a permanent magnet), the result is called a synchronous motor because the rotor will rotate synchronously with the rotating magnetic field produced by the ...
In operation as a motor, the stator flux rotation is at the synchronous speed, which is faster than the rotor speed. This causes the stator flux to cycle at the slip frequency inducing rotor current through the mutual inductance between the stator and rotor. The induced current create a rotor flux with magnetic polarity opposite to the stator ...