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Inventive Wedge Using Bandage, Resulting in Higher Fill Factor

IP.com Disclosure Number: IPCOM000198276D
Original Publication Date: 2010-Aug-23
Included in the Prior Art Database: 2010-Aug-23
Document File: 3 page(s) / 356K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

In wind power applications, preformed coils are preferred to other alternatives due to their high reliability. Due to their solid performed structure, these coils need to be radially inserted into the slots as illustrated in Figure 1, thereby the slots need to be completely open near the air-gap. The wedge can be made of magnetic or non-magnetic material, while the non-magnetic wedge is preferred due to its higher reliability. Figure 1 shows a typical picture of the conventional preformed coils, numerated 2 and 5, and the wedge, numerated 4, used to keep the coils fixed inside their slots. The parts in Figure 1 are: 1. The stator slot, 2. The Preformed coil belonging to phase A, 3. The stator teeth, 4. A typical conventional wedge, 5. The preformed coil corresponding to phase C, 6. A typical cavity punched through lamination to allow for wedge insertion. To insert the wedge above the coils and close the open slots, the stator laminations are punched to have some cavities near the slot opening, numerated 6 in Figure 1. This extra punching in the lamination destroys magnetically some region of the stator material near to the punching location and thereby results in unwanted performance like lower output torque or unpredictable ripple and cogging torque values. Furthermore, it can be theoretically shown that these cavities, in case of non-magnetic wedge, increase the cogging and ripple torque due to magnetic saturation of the narrow corners of the stator teeth.

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Inventive Wedge Using Bandage, Resulting in Higher Fill Factor

Idea: Mohammad Kimiabeigi, DK-Brande

In wind power applications, preformed coils are preferred to other alternatives due t reliability. Due to their solid performed structure, these coils need to be radially inse as illustrated in Figure 1, thereby the slots need to be completely open near the air- can be made of magnetic or non-magnetic material, while the non-magnetic wedg its higher reliability. Figure 1 shows a typical picture of the conventional preform and 5, and the wedge, numerated 4, u
1 are: 1. The stator slot, 2. The Preformed coil belonging to phase A, 3. The stato conventional wedge, 5. The preformed coil corresponding to phase C, 6. A typical through lamination to allow for wedge insertion.

To insert the wedge above the coils and close the open slots, the stator laminations have some cavities near the slot opening, numerated 6 in Figure 1. This extra punch lamination destroys magnetically some region of the stator material near to the p thereby results in unwanted performance like lower output torque or unpredicta torque values. Furthermore, it can be theoretically shown that these cavities, in wedge, increase the cogging and ripple torque due to magnetic saturation of the na stator teeth.

The novel idea proposes that right after insertion of the coils, similar to the known pro fretting/bandaging the magnets in high speed motors, the surface of the stator is Figure 2) using a robust material similar to that used in magnet fretting. The ban example fiberglass or epoxy or the known special composite that absorbs the re Pressure Impregnation) process and becomes stiff. After wrapping the bandage a surface, the VPI process can be done so that the gaps between the bandage, stato the coils are filled by resin and the bandage becomes stiffer in its place.

The bandage can fully or only partially cover the stator surface in axial direction, dep required strength to keep the coils insi
preferred to be composed of more than one segment for ease of transportation. In t bandaging of the stator surface can be done partially with regards to the axial direct Figure 2b. This way, there will be tact (i.e. unbandaged) areas of the stator yoke on whi bars, numerated 8 in Figure 2, can be welded or mechanically fixed. The nei
will also be mechanically fixed, for example, welded to the same joint bars suc
are fixed together forming a complete round stator. The joint bars are full 360 d
in Figure 2, only a fraction of them is displayed.

The parts in Figure 2 are: 1. The stator tooth, 2. The stator yoke, 3. The stator sl corresponding to phase A in a 3-phas...