Report KD 699 can be copied for free from my website:
www.kdwindturbines.nl at the menu KD-reports. The tittle of this report is: "Calculations executed for the 3-bladed rotor of the VIRYA-4.4 windmill (lambda design = 5.25, stainless steel blades) using a 34-pole PM-generator for coupling to a centrifugal pump with a 1.1 kW asynchronous motor". The 34-pole PM-generator is described in report KD 614.
KD 699 describes a new way of water pumping for which a 34-pole PM generator is used which supplies a high frequency already at low rotational speeds. The generator can therefore be coupled directly to the asynchronous motor of a standard centrifugal pump. So this windmill has a so called "electrical shaft" in between the windmill rotor and the pump. Advantages of this option are that the windmill can be placed at a large distance from the well, that the cable losses are low because of the high voltage, that it is also possible to drive other equipment than a pump if this equipment accepts variation of the rotational speed and that it can be used for high voltage battery charging. If the generator is provided with a low voltage winding, the VIRYA-4.4 can also be used for 24 V battery charging.
