KD 670 reviewed

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.

KD 683 reviewed

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.

KD 683 added

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.

KD 681 added

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”.

KD 679 reviewed

Chapter 3 of KD 679 has been reviewed. The older version describes the calculation of the flux density in the air gap for a synthetic stator sheet. The reviewed version describes the calculation of the flux density for a steel stator sheet.

KD 678 reviewed

A new chapter 7 has been added to report KD 678 about the VIRYA-1.02 and the measurements of the generator. Chapter 7 gives a discussion of the measuring results and it is explained at what places energy is lost if the generator runs at 575 rpm and supplies an electrical power of 27 W.

KD 416 reviewed again

A new chapter 3 has been added to report KD 416 about drag machines. Chapter 3 gives the Cp-lambda curve for only the cup which is moving in the direction of the wind.

KD 601 reviewed

Report KD 601 about a self starting Darrieus rotor has been reviewed. The estimated Cp-lambda and Cq-lambda curves given at chapter 5 have been changed. For very low lambda values, the rotor works as a drag machine and the Cq-lambda curve now has a small positive Cq value for values of lambda smaller than 0.3. The maximum Cp has been reduced from 0.35 up to 0.3.

KD 416 reviewed

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.

KD 599 reviewed

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”.