Reports KD 608 and KD 571 reviewed, Report KD 626 added

Reports KD 608 and KD 571 have been reviewed. Report KD 626 has been made public. Report KD 626 describes the VIRYA-1.25AF windmill. This windmill has an axial flux generator which is made from the front hub of a mountain bike just as it is also done for the VIRYA-1. However, the VIRYA-1.25AF generator has a steel stator disk which gives it a higher maximum torque level and a higher maximum power than for the synthetic stator disk of the VIRYA-1 generator. The VIRYA-1.25AF has a stainless steel rotor with a diameter of 1.25 m. This is really a simple design with an acceptable power curve.

VIRYA-2.2 replaced by VIRYA-1.81

The manual of VIRYA-2.2 is replaced by the manual of the VIRYA-1.81. The VIRYA-2.2 had a steel stator disk and it was expected that the heat generation in this sheet could be too high at high rotational speeds. The VIRYA-1.81 makes use of the same magnets but has a synthetic stator disk and no heat will be dissipated in this disk. As the maximum torque level for a synthetic stator sheet is lower than for a steel stator disk, the rotor diameter is reduced from 2.2 m up to 1.81 m. The design report of the VIRYA-2.2 with report number KD 607 is cancelled and replaced by the design report of the VIRYA-1.81 with report number 631.

KD 595 reviewed

A new chapter 6 has been added to public report KD 595 in which measurements on a Chinese axial flux generator are given. The generator has been tested in combination with the stainless steel VIRYA-1.65 rotor from September 2015 up to March 2017. The windmill worked well but the rotor was too noisy. A new more silent rotor with wooden blades is designed in report KD 630 (not public).

Note “A staff notation without flats and sharps” reviewed

The note “A staff notation without flats and sharps”, which can be found at the menu “No wind energy”, is devided into four chapters. Chapter 4 is new and describes a very compact new staff notation for which all twelve chromatic tones in an octave have an unequivocal name and with which it is possible to write eight octaves at two identical staffs.

Notitie “Een notenschrift zonder mollen en kruizen” herzien

De notitie “Een notenschrift zonder mollen en kruizen”, die staat onder het menu “No wind energy”, is onderverdeeld in vier hoofdstukken. Hoofdstuk 4 is nieuw en beschrijft een zeer compact nieuw notenschrift waarvoor alle twaalf chromatische tonen in een octaaf een eenduidige naam hebben en waarmee het mogelijk is om acht octaven vast te leggen op twee identieke notenbalken.

KD 490 reviewed

At page 7 of KD 490: “Water pumping with a windmill” a short piece has been added about report KD 624 in which an alternative 46-pole PM-generator of the VIRYA-6.5 is described.

KD 571 reviewed

A new chapter 11 has been added to report KD 571 in which the VIRYA-1.36 rotor and PM-generator are described. Chapter 11 gives an alternative of circular magnets in stead of square magnets. The advantages of circular magnets are: 1) The total magnet costs are lower. 2) The fluctuation of the AC voltage is more sinusoidal. 3) Mounting is easier.

KD 35 Nederlands

Het rapport KD 35 dat oorspronkelijk in het Engels geschreven is, werd afgelopen week vertaald in het Nederlands en heeft dan als titel: “Rotorontwerp en matching voor horizontale as windturbines”. KD 35 geeft de basisbegrippen van de aerodynamica van windmolens, een methode voor het ontwerpen van rotoren en een methode om te controleren of de ontworpen rotor bij een bepaalde generator past. Ik verwacht dat er in Nederland belangstelling is voor een Nederlandse versie van KD 35. Een Nederlandstalig rapport is ook beter geschikt voor Nederlandstalig onderwijs.

KD 35 reviewed

Recently I wrote a Dutch translation of report KD 35: “Rotor design and matching for horizontal axis wind turbines”. During making of this translation, I have found certain small typing errors in the English version and I also made some small modifications. So the English version was modified and now has the same content as the Dutch version.

KD 608 reviewed

Chapter 10 is added to report KD 608 about the 8-pole VIRYA-1 generator. In this chapter 10 an alternative steel stator disk is described which will give the generator a higher maximum torque level. A steel stator disk might also be an alternative if the specified material for the original synthetic stator sheet isn’t available. It is expected that the rise of the temperature of the stator disk due to eddy currents, is acceptable.