KD 708 added

Report KD 708 has been added to the menu KD-reports. The title of this report is: “Ideas about a 22-pole permanent magnet generator for the VIRYA-2.7 windmill using a 4-pole, 3-phase, 1.5 kW asynchronous motor frame size 90 and 27 1/2 neodymium magnets size 40 * 10 * 4 mm”.

Notitie naafdynamo aangepast

De notitie: “Ideeën over een ideale naafdynamo” werd aangepast. Het aantal polen werd verhoogd van 10 naar 12 en het aantal spoelen werd verhoogd van 6 naar 9. Er werd een inleiding toegevoegd waarin proefjes met een 8-polige banddynamo en een 28-polige naafdynamo worden beschreven. De Engelstalige versie komt hierbij te vervallen.

KD 551 reviewed

The new chapters 7 and 8 have been added to report KD 551 in which aerodynamic characteristics are given for rectangular flat plates with different aspect ratios. Chapter 7 is called: “Determination of the moment coefficient Cmh around a point H for a square plate”. Chapter 8 is called: “Determination of the moment coefficient Cmh around a point H for an aspect ratio 1 : 5”. This information is important if a vane is rotating around an axis which is lying behind the airfoil nose. This axis should not be taken too far from the airfoil nose other wise the vane becomes instable.

KD 341 reviewed

A new chapter 8 “Experiments with Chinese axial flux generators of Hefei Top Grand” has been added to report KD 341: “Development of the permanent magnet (PM) generators of the VIRYA windmills”.

KD 707 added

Report KD 707 has been added at the menu KD-reports. The title of this report is: “Replacement of the original radial flux PM-generator of the VIRYA-4.2 by the axial flux PM-generator of Hefei Top Grand type TGET380-10KW-1200R for 48 V battery charging”.

Drawings of the VIRYA-4.2 windmill are no longer available. The main goal of writing this report KD 707 is not to introduce a new VIRYA design but to find the procedure how the Pmech-n and Pel-n curves for a 48 V battery load can be estimated from the specification of the manufacturer. Making this knowledge available, is the reason why this report is made public.

KD 705 added

Report KD 705 has been added at the menu KD-reports. The tittle of this report is: “Ideas about the use of the 3-bladed VIRYA-3B3 rotor (lambda design = 6.5) in combination with the axial flux generator of Hefei Top Grand type TGET320-1KW-350R”. The main goal of this report is not to present a new VIRYA windmill but to explain how the specification of the supplier of a certain PM-generator can be transformed into the wanted Pmech-n and Pel-n curves of the generator. The characteristics of the VIRYA-3B3 rotor have been used as an example to check the matching and to derive the Pel-V curve.

KD 704 added

Report KD 704 has been added at the menu KD-reports. The tittle of this report is: “Ideas about a piston pump with a floating valve for the VIRYA-3.6L2 windmill for irrigation of farmland from a river or a lake”.

The first windmill which was equipped with a pump with a floating valve is the CWD 2000 which was tested in the period 1989-1990 at the Eindhoven University of Technology. The output was much higher than for a normal piston pump with the same starting wind speed. The idea of a piston pump with a floating valve for the bigger VIRYA-3.6L2 windmill is especially of interest for irrigation as large flows are needed for this purpose.

KD 703 added

Report KD 703 has been added at the menu KD-reports. The tittle of this report is: “Ideas about a 4-bucket Savonious rotor called the VIRYA-1.45 for driving a positive displacement pump”. A photo of a scale model of the rotor scale 1 : 5 is given on the front page of this report.

KD 702 added

Report KD 702 can be copied for free at the menu KD-reports. The tittle of this report is: “Ideas about the 8-bladed rotor of the VIRYA-0.54 windmill (lambda design = 1.25, pentagonal aluminium blades) coupled to a Nexus hub dynamo for 12 V battery charging”.

The VIRYA-0.54 is a very simple and light windmill without a head and a safety system which is placed on top of a bamboo pole. The rotor is turned in the wind by manually turning of the bamboo pole.