Understanding the Continuity of Current in a Rotating Magnetic Field

In summary, the conversation discusses the calculation of net mmf due to currents in two points, pt1 and pt2. The speaker is confused about the region between these points and whether a similar calculation is needed. They also question the advantage of continuous current between pt1 and pt2 and ask if the black arrow cannot stop between stator windings. The speaker also mentions the role of true sine wave currents in creating a smooth rotating magnetic field and compares it to a stepper motor which uses step currents and can hold the rotor between poles.
  • #1
PhysicsTest
238
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TL;DR Summary
Does the magnetic field rotate continuously or discrete.
I am analyzing the rotor magnetic field, i feel i understand the basic concept but have few clarifications.

1603550647150.png


At pt1, the net mmf due to currents
##i_a = i_{max}; i_b = -\frac{i_{max}} 2 ; i_c = -\frac{i_{max}} 2## is ##\frac {3F_{max}} 2##
1603550483841.png

Similarly i can do for Pt2. But my confusion is the region between the points pt1 and pt2, do i need to calculate similar to above. This question i am asking because if i see this website https://en.wikipedia.org/wiki/Rotating_magnetic_field ( i came to know from here) if share a screen shot from the website. The black arrow cannot stop in between the stator windings is my guess. Am I correct? What is the advantage of the continuous current in between pt1 and pt2?
1603550949200.png
 
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  • #2
PhysicsTest said:
The black arrow cannot stop in between the stator windings is my guess. Am I correct?
If the currents are true sine waves then the magnetic field will be rotating reasonably smoothly.

As the current through two pole windings are momentarily equal as they pass, the two poles will have the same magnetic flux so the gap between will be magnetically invisible to the rotor as it passes.

If it was a stepper motor, fed with step currents rather than sine waves, then the field will step and the rotor would be able to be held between the poles.
 

1. What is a rotating magnetic field?

A rotating magnetic field is a magnetic field that changes direction and magnitude over time, creating a rotating pattern. This can be created by using multiple magnetic fields that are out of phase with each other, or by using a single magnetic field that is rotating in space.

2. How does a rotating magnetic field produce current?

When a conductor, such as a wire, is placed in a rotating magnetic field, the changing magnetic field induces an electric current in the conductor. This is due to Faraday's law of induction, which states that a changing magnetic field will induce an electric field, and thus a current, in a conductor.

3. What is the significance of understanding the continuity of current in a rotating magnetic field?

Understanding the continuity of current in a rotating magnetic field is important in a variety of applications, such as electric motors and generators. It allows us to control the direction and magnitude of the induced current, which is essential for the proper functioning of these devices.

4. How does the direction of the rotating magnetic field affect the direction of the induced current?

The direction of the rotating magnetic field determines the direction of the induced current. If the magnetic field is rotating clockwise, the induced current will flow in one direction, and if the magnetic field is rotating counterclockwise, the induced current will flow in the opposite direction.

5. What is the relationship between the frequency of the rotating magnetic field and the frequency of the induced current?

The frequency of the induced current is directly proportional to the frequency of the rotating magnetic field. This means that as the frequency of the magnetic field increases, the frequency of the induced current also increases. This relationship is important in designing and optimizing electric motors and generators.

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