Adriaan tells me:
“Recently I have written report KD 645 about the design of a new type 10-pole radial flux PM-generator with no iron in the coils and a simple 1-layer winding. This report can be copied for free from my website www.kdwindturbines.nl at the menu KD-reports.”
This is a ten pole design with 3-phase output using a standard motor body to enclose the working parts. It’s great for keeping the magnets dry! There is no iron in the stator which should mean it will be easy to start with no iron loss. I suspect there will be some eddy current loss in the motor body (not shown in drawings) that encloses the coils. Cooling of the coils will not be very effective though, which will place a limit on the continuous power output of the turbine.
The magnetic flux will be very weak and the actual performance (voltage per coil-turn per rpm) is yet to be determined. Adriaan tells me “the costs of a PM-generator with an iron stator and about the same maximum torque level are much lower.”
“I have no intention to build a prototype and test it but it would be good if someone else would test this idea. If the generated heat in aluminium is too high, one should use a housing made out of a synthetic material.”
PS: Adriaan further tells me he has designed a very small version “I have designed a 10-pole hub dynamo for a bicycle using the same principles as used for the 10-pole dynamo as described in KD 645. However, for the hub dynamo the rotating armature is at the outside and the stator with coils is at the inside. Although this dynamo is especially designed to be used in a bicycle, it might also be possible to use it in a very small wind turbine with a diameter of about 1 m. The idea is described in the note: “Ideas about an ideal hub dynamo” which can be found at my website: www.kdwindturbines.nl at the bottom of the menu “No wind energy”. There is also a Dutch version of this note which I have sent to a Dutch bicycle magazine to be published but I don’t know yet if they will accept the note or a summary of it.”