KD 617 added

Report KD 617 from November 2016 has been added to the menu “KD-reports”. The tittle of this report is: “Design report of the VIRYA-2.02 rotor (lambda design = 6, B = 2, tapered stainless steel blades). The geometry of the VIRYA-2.02 rotor was already given in chapter 5 of report KD 616 but the design calculations are given in KD 617.

The 2-bladed VIRYA-2.02 has blades which are made from a 2 mm stainless steel sheet size 2 * 250 * 833 mm. This sheet is cambered first and then ground into two tapered blades. The two blades are connected to each other by a stainless steel connecting strip size 3 * 166 * 416 mm which is cambered at the ends and twisted.

KD 678 reviewed

Report KD 678 has been reviewed totally. The previous rotor had three separate spokes but it was expected that it is difficult to make the hole pattern in these spokes accurately enough to guarantee an exact angle of 120° in between the three blades. So the new rotor has a hub plate made out on one piece of 1.5 mm stainless steel sheet. The blades are made longer to minimise the dimensions of the hub plate. This rotor has a higher maximum Cp, a higher starting torque coefficient and it also looks better.

KD 678 added

Report KD 678 has been added to the menu KD-reports. The tittle of this report is: “Calculations executed for the 3-bladed rotor of the VIRYA-1.02 windmill (lambda design = 3.5, 15° folded stainless steel blades) meant to be couples to the VIRYA-1.25AF generator”. The 3-bladed VIRYA-1.02 is an alternative for the 2-bladed VIRYA-1 or the 2-bladed VIRYA-1.25AF.

KD 645 reviewed

A new chapter 6 has been added to report KD 645. The tittle of this chapter is: “Alternative winding with 15 coils”. The original winding has a 1-layer winding with two coils per phase, so totally six coils. The alternative winding has no sleeves in the Delrin bush but thirty 8 mm holes. The armature has a length of 80 mm in stead of 100 mm and one magnet size 80 * 20 * 10 mm is used in each groove. It is expected that the reduction of the power because of the shorter armature is compensated because now per phase five coils are used in stead of two coils.

Extended specification reviewed

The extended specification at the menu VIRYA-folders has been reviewed. The VIRYA-1.75W, the VIRYA-1.8W and the VIRYA-2.22 have been added to the extended specification.

KD 676 added

Report KD 676 has been added at the menu KD-reports. The tittle of this report is: “Calculations executed for the 2-bladed rotor of the VIRYA-2.22 windmill (lambda design = 5, stainless steel blades) using the axial flux PM-generator of Hefei Top Grand model TGET260-0.5KW-350R”. The VIRYA-2.22 has also been added to the folder of the VIRYA-1.75 W and the VIRYA-1.8W.

KD 608 reviewed

Report KD 608 has been reviewed. The thickness of the aluminium rotor blades has been increased from 1.5 up to 2 mm. A new chapter 9 has been added in which the use of a steel stator sheet has been investigated. Some minor changes have been made in the report.

KD 672 added, KD 490 reviewed

Report KD 672 has been added at the menu KD-reports. The tittle of this report is: “Use of the VIRYA-1 or the VIRYA-1.25AF for pumping of drinking water using a 12 V battery and a pump with a 12 V, DC motor”. Although the VIRYA-1 is a small windmill with a rotor diameter of only 1 m, it is big enough to pump a flow q of 200 litres water per day against a height H = 17 m at a wind speed less than 3 m/s.

Report KD 490 “Water pumping with a windmill” has been reviewed such that report KD 672 is now also mentioned.

De rechte schuiftrompet in C

Onder het menu “No wind energy” werd de Nederlandstalige notitie “De rechte schuiftrompet in C” toegevoegd. Deze notitie beschrijft een zeer eenvoudig nieuw blaasinstrument zonder ventielen en zonder bochten in de hoofdbuis.

KD 671 added

Report KD 671 has been added to the menu KD-reports. The title of this report is: “Translation of parts of report R-668-A “Optimalisering van een windservo” (Optimizing of a wind servo) from Dutch into English. Ideas about the VIRYA-2B8″.

Report R-668-A of the Wind Energy Group of the University of Technology Eindhoven was already written in 1984 by the student J. Swinkels. I was one of his supervisors. As this report is no longer available, I thought that it is useful to translate the most important part of it and make it public again.

Report KD 671 gives the wind tunnel measurements for a wind servo for the most promising blade angle of 30° for seven different yaw angles. Chapter 4 gives correction for wind tunnel blockage for the rotor perpendicular to the wind. Chapter 5 describes the VIRYA-2B8 rotor which is about congruent to the measured wind tunnel model.