Here's my technical partner's, Larry Ludwig's, assessment. In general he thinks it would be good for producing power at very low wind speeds as it would reduce EMF drag.
Skimmed the discussion and drawings. The only serious advantage to this is that low wind speeds will still produce pulses (less system EFM drag) which can be rectified so that you can always produce some voltage. Electronically the voltge can be built to a higher level with a chopper circuit. This might be useful in a battery based system where trickel charge (high voltage, very low current) helps to maintain the charge. If you were to look at there diagrams and draw lines to the top of each pulse you would get a sine wave which is what overlapping coils whould produce. In an alternator, these three overlapping coil voltages are rectified to a pure dc. The three coil set allows for less ripple smoothing to have to ocur so that less loss occurs in the rectification and smoothing circuit. If our desire is to always generate some voltage, even at low wind speeds: we could have our PIC keep a low drag PM pulsed alternator engaged at low RPM and a High drag, High voltage generating alternator swithched in ( and the other swithed out) at higher RPMs. Then we could have retification circuits for each one designed around what were doing with the outputs. The High RPM could be a direct feed to the system under use, with a small bleed to the batteries. The low RPM system could only feed/charge the battery. This is typically the type system I had envisioned for a home power system. A high voltage battery set with an inverter for producing AC at high output periods and a low current, high voltage electronic circuitry for just charging the batterys during low output periods. I could talk to Pete about an electriclly actuated clutch system or a mechanicat RPM activated clutch system the we could read electrically to determin system operation parameters/switching. [ Parent ]
I presented this design for the case of charging a battery where pulsed dc doesn't matter. That is, while this will have more ripple than a three phase system, for charging a battery it doesn't matter.
I don't see any reason why this alternator couldn't be made to produce more power at higher wind speeds by introducing centrifugally operated iron cores for the coils. At low rpms they are retracted. At a certain point they are inserted in a controlled manner. This would be easiest to do if the coil assembly rotated. With the magnet assembly rotating it would be necessary to mount the centrifugal weights on the back of the rotor and transmit their effect through the shaft by the use of a rod. The question is how something like this would compare in cost to adding a second alternator?
GeoM[ Parent ]
