Pictured above are the Westwind Stator on the left and an encapsulated axial flux stator on the right. Although much has been claimed about the supposed benefits of generator windings being "encapsulated" and the generator being of an "axial flux design", Westwind choose not to use this design for we believe different.
J.A. Graham Renewable Energy Services have more experience, more enthusiasm and more concern for the quality of our product than other competitors.

Encapsulated is when it is sealed after winding, usually by surrounding the entire stator in an epoxy resin.

If you approach any windings services they will inform you that the traditional method is still best, they are supplying rewound motor / generator parts everyday and do not want any poorly insulated parts coming back at them. When original windings are made they are submerged in a bath of shellac (a natural polymer), and this works into the windings due to its density. Through the application on heat, the product is cured. Once cured it is not soluble, and is a good transmitter of heat.

Epoxy Resins are not a good conductor of heat, something a stator of any type needs no matter how efficient. There is also no possibility of the air circulating in these to cool the windings. This poor heat conduction causes more problems as if the windings change temperature, the epoxy does not expand as rapidly as the windings; leading to the epoxy cracking - and this looses the insulation.

Axial Flux is a good idea and it does produce electricity, but for the best part is not more efficient than many others; even though it lets the turbine start to rotate very easily. This does not however result in much, if any, useful power being produced. It does mean the turbine appears that it is producing; however, effectively it is only doing "miles" it has no need to. There is also the problem that most of this type of stator has to be hand wound leaving margin for error, for example, during the hundreds of turns of wire there is almost certainty there will be a miscount. Axial Flux is established for a long period, but the vast majority of manufacturers use the "normal" PM (permanent magnet) generators.

Westwind stators are machine wound and machine punched therefore repetition is achievable; therefore it is almost an impossibility for them to have any difference in outer diameter. Westwind generator drums / cans are machined to a predetermined sized also that are fitted with magnets of a predetermined size. We have no shimming or adjusting to be done, and as a result of these factors is that Westwind can operate with a consistent air gap of 1mm.

Due to the high quality of manufacture Westwind generators give consistent performance levels whether on the dyno or in the air operational; unlike those that are shimmed, adjusted, hand wound and can have serious differences in performance from one machine to the next. Even our test machines cannot be adjusted in any way to enhance their performance, they no different or carry any variation in comparison to the production models.

Westwind opted to stay with a traditional stator albeit, a very efficient one. We use thin laminates with an intricately designed slot. This is not as simple as it sounds, there was a very large investment made by the Australian Government to design these generators and these slots were a crucial part of the design. Westwind's generator is 95% efficient due to its design, leading to less heat build up meaning an excellent power to blade swept area ratio.

Westwind could have used both Axial Flux and encapsulation, it would actually be cheaper for us in addition to this, but we and our existing customers / distributors agree that a cheap product is not the answer.

• The first part is a rotating section commonly known as the rotor, which has pairs of magnetic poles.



• The second part, the stator, is simply fixed coils of wire; also known as the A.C. stator.