Report KD 684 has been added at the menu KD-reports. The tittle of this report is: “Derivation of the formula for the cone angle epsilon for a constant chord blade which is connected to the hub by a hinge”. The formula for the cone angle epsilon was already derived in report R 409 D from 1980 but as this report is written in Dutch and no longer available, the derivation is now given in this public report KD 684. The formula is used to calculate the bending stress at the blade root of for instance the VIRYA-3B3 rotor as described in chapter 8 of report KD 484.

Chapter 6 of KD 670 has been reviewed. The calculation of the load resistance R for star connection has been changed. An alternative resistance load with three 72 Ohm resistors connected in delta is given. These resistors can be switched in sequentially to realise a better matching at low wind speeds. A new chapter 9 has been added in which the starting behaviour for a resistor load is investigated. Switching from star to delta is also an acceptable option to improve the starting behaviour for a resistor load.

A new chapter 5 has been added to report KD 683. In this chapter an alternative 4-pole armature is given for which the armature grooves are inclined just as it is also done for my older VIRYA generators.

Report KD 683 has been added at the menu KD-reports. The tittle of this report is: “Ideas about a 4-pole, 3-phase permanent magnet generator using the housing of an asynchronous motor frame size 80 and four neodymium magnets size 80 * 20 * 10 mm with a magnet orientation such that the fluctuation of the sticking torque is minimal”. This 4-pole PM-generator makes use of the same principle to flatten the fluctuation of the sticking torque as used for the 8-pole PM-generator as described in report KD 681. An advantage of using the housing of a 4-pole motor is that the standard winding can be used.

Report KD 681 has been added to the menu KD-reports. The tittle of this report is: “Ideas about an 8-pole, 3-phase permanent magnet generator using the housing of an asynchronous motor frame size 80 and four neodymium magnets size 80 * 20 * 10 mm with a magnet orientation such that the fluctuation of the sticking torque is minimal”.