Articles for april 2017

KD 340 reviewed

Report KD 340: Rectification of 3-phase VIRYA windmill generators is reviewed. The curves which give the current I as a fuction of the phase angel have been modified such that the DC current for delta rectification is now lying a factor square root of 3 higher than the curve for star rectification. It was just the opposite and although the curves are relative, this might be confusing.

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).