Table 1 out of report KD 416 about drag machines has been extended. The Cp-lambda and Cq-lambda curves have been added in figure 2 and figure 3.
A new link to the report: “Wind tunnel blockage corrections: an application to vertical-axis wind turbines” has been added as point 2.8 in report KD 599: “Measurements of Savonious rotors available in the Internet”.
Report KD 679 has been added to the menu-KD reports. The tittle of this report is: “Development of an 8-pole, 3-phase axial flux permanent magnet generator for the VIRYA-1 windmill using a bicycle hub and 8 neodymium magnets size round 25 * 12 mm and a stator made out of galvanised steel sheet”. Report KD 679 replaces report KD 608 which is cancelled. Report KD 626 in which the VIRYA-1.25AF rotor is described is cancelled too because the matching in between rotor and generator isn’t good enough for the measured generator characteristics. The generator characteristics are given in report KD 678 which has been reviewed. Report KD 672 has been reviewed too. The extended specification and the folders of the free VIRYA designs which are given at the menu KD-folders have been reviewed too.
A new chapter 6, “Generator measurements”, has been added to report KD 678. A teacher of a technical school has built the 8-pole generator of the VIRYA-1.02 and I have measured this generator on my test rig for a 12 V battery load. The torque level of the generator appeared to be lower than expected but the matching in between rotor and generator is still acceptable. The maximum electrical power for the rated wind speed of 8 m/s is about 24 W.
The folder about Kragten Design at the menu “Home” has been slightly modified.
Some small mistakes have been removed from report KD 670 about the VIRYA-5.2.
The link in this report to the report: “Wind Tunnel Performances Data for Two- and Three-bucket Savonius rotors” has been changed as the original link is no longer working.
Rapport KD 137 kan gratis gekopieerd worden van het menu “No wind energy”. De titel van dit Nederlandstalige rapport is: “De dubbelzuigervoetpomp”. Dit rapport werd al in 2003 geschreven. Pagina 3 werd in Juli 2019 enigszins aangepast zodat nu naar courante andere KD-rapporten verwezen wordt. Dit rapport staat niet onder het menu KD-reports omdat het niet over windenergie gaat maar over een pomp die met de voeten aangedreven wordt. In figuur 1 van KD 137 wordt een gedetailleerde tekening van de pomp gegeven.
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.
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.