# Rotating Magnetic Field

Published on 24/2/2012 & updated on Friday 11th of May 2018 at 04:47:28 PMHOME / ELECTRIC MOTOR / SYNCHRONOUS MOTOR

**rotating magnetic field**is produced which rotates in synchronous speed.

**rotating magnetic field**. For that, we will first imagine one stator of an electric motor where three-phase winding is physically distributed in the stator core in such a manner that winding of each phase is separated from other by 120

^{o}in space.

Although the vector sum of three currents in a balanced three-phase system is zero at any instant, but the resultant of the magnetic fields produced by the currents is not zero rather it will have a constant non-zero value rotating in space in respect to time.

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The magnetic flux produced by the current in each phase can be represented by the equations given below. This is a similar representation of current is a three-phase system as the flux is cophasial with the current.
Where, φ_{R}, φ_{Y} and φ_{B} are the instantaneous flux of corresponding Red, Yellow and Blue phase winding, φ_{m} amplitude of the flux wave. The flux wave in the space can be represented as shown below.
Now, on the above graphical representation of flux waves, we will first consider the point 0.
Here, the value of φ_{R} is
The value of φ_{Y} is
The value of φ_{B} is
The resultant of these fluxes at that instant (φ_{r}) is 1.5φ_{m} which is shown in the figure below.
Now, on the above graphical representation of flux waves, we will consider the point 1, where ωt = π / 6 or 30^{o}.
Here, the value of φ_{R} is
The value of φ_{Y} is
The value of φ_{B} is
The resultant of these fluxes at that instant (φ_{r}) is 1.5φ_{m} which is shown in the figure below. here it is clear thet the resultant flux vector is rotated 30^{o} further clockwise without changing its value.

Now, on the graphical representation of flux waves, we will consider the point 2, where ωt = π / 3 or 60^{o}.
Here, the value of φ_{R} is
The value of φ_{Y} is
The value of φ_{B} is
The resultant of these fluxes at that instant (φ_{r}) is 1.5φ_{m} which is shown in the figure below. here it is clear thet the resultant flux vector is rotated 30° further clockwise without changing its value.

Now, on the graphical representation of flux waves, we will consider the point 3, where ωt = π / 2 or 90^{o}.
Here, the value of φ_{R} is
The value of φ_{Y} is
The value of φ_{B} is
The resultant of these fluxes at that instant (φ_{r}) is 1.5φ_{m} which is shown in the figure below. here it is clear thet the resultant flux vector is rotated 30^{o} further clockwise without changing its value.
In this way we can prove that the due to balanced supply applied to the three pfase stator winding a rotating or revolving magnetic fiels is established in thew space.

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