Leakage Flux Inside a Slot of an AC Machine (dual stator)

In summary: Therefore, the (3) and (4) equations are necessary in order to accurately calculate the total flux in the slot. In summary, the conversation discusses the use of Ampere's law to find the magnetic field strength in a slot of an AC machine. The equations (3) and (4) are used to calculate the total flux in the slot by considering the contribution from each individual conductor. This is necessary because when integrating the dφs equation, the total flux is calculated by summing up the contributions from each conductor. The addition of a third dimension (z-axis) in the image file helps clarify the concept.
  • #1
BlackMelon
45
7
Hello All,

Please see the attachments. The pdf file is the IEEE paper I'm reading. Figure 1 show a slot of the AC machine similar to the front view of the picture below:
1657379046511.png


But in one slot, they fit two sets of conductors. The first set carries current i1 in total. The second set carries current i2. They study the leakage flux path just like in the figure 1. So, they apply the Ampere's law in (1) to find the magnetic field strength (hs(Y)) first. However, I am curious about the (3) and (4) equation. Why do we have to multiply dφs by nSi to get dφsi and then integrate it to get φsi in (4) ? Can we just integrate the (2) equation to get φsi?

Ps. To my understanding, please see the image file (drawn by MS paint). I align the x-axis and y-axis as those in the IEEE paper. But I add another dimension (z-axis) to clarify the constant "L". The number conductors was taken into account in the (1) equation already. L*dY is the area perpendicular to u0*hs(Y). So, multiply these two terms and integrate the product along the Y-axis should get the total flux for a certain area.
 

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  • #2
The answer to your question is that when you integrate the dφs equation (2) to get φsi, you are actually integrating over the entire area of the slot. This is because when you integrate, you are summing up all the individual contributions from each current carrying conductor in the slot. The equation (3) and (4) are used to calculate the contribution from each individual conductor, which is why it is multiplied by the number of turns (nSi). By integrating this product, we can then get the total flux (φsi) in the slot.
 

FAQ: Leakage Flux Inside a Slot of an AC Machine (dual stator)

What is leakage flux inside a slot of an AC machine?

Leakage flux inside a slot of an AC machine refers to the magnetic flux that does not follow the intended path through the air gap and stator core, but instead "leaks" through the slot openings. This flux can cause energy losses and affect the performance of the machine.

How does leakage flux affect the performance of an AC machine?

Leakage flux can cause energy losses in an AC machine, leading to reduced efficiency and increased heat generation. It can also cause variations in the magnetic field, resulting in torque ripple and vibrations. This can affect the overall performance and reliability of the machine.

What factors contribute to leakage flux inside a slot of an AC machine?

Leakage flux can be caused by various factors, including the shape and size of the slot, the magnetic properties of the stator core and rotor, and the air gap between the stator and rotor. It can also be affected by the design of the winding and the operating conditions of the machine.

How can leakage flux be reduced in an AC machine?

There are several ways to reduce leakage flux in an AC machine, including optimizing the design of the stator and rotor, using materials with high magnetic permeability, and minimizing the air gap between the stator and rotor. Proper insulation and winding techniques can also help reduce leakage flux.

What are the consequences of high leakage flux in an AC machine?

High leakage flux can lead to increased energy losses, reduced efficiency, and potential damage to the machine due to excessive heat generation. It can also cause vibrations and noise, affecting the overall performance and reliability of the machine. Therefore, it is essential to minimize leakage flux in AC machines for optimal operation.

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