The energy is stored in the mag fld, not the inductor. Also, I've seen orbos that seemed to have a core with the toroid, and some that didn't, or at least it certainly didn't look like there was a core. I also was under the impression that the stator cores were NOT PMs, but simply iron cores.
A few more thoughts, and I'll spare you the useless speculations... - Work is definitely being done as the permanent magnets on the rotor are being attracted to (accelerating towards) the stator cores. ABD seemed to imply, or state, that the only time any work was being done was after the rotor PMs passed the toroids... He also stated that the toroids must be fed constant current for a significant period after that point... I believe this is not the case. - From the oscilloscope screen shots, and contrary to ABD's comment, the toroids are only being pulsed for a short time as the rotor magnets pass TDC to overcome the cogging effect. From other PM motors like Sprain and Butch LaFonte, the single electromagnet (at the end of the PMs making up the stator) only needs a very short pulse to allow the rotor to pass the cogging point. The time for the mag-fld to build up and then collapse is considerably longer than the electric pulse. - When I mentioned some of the things that Thane Heins had learned over his time at Ottowa U, this forum pretty much dismissed it as nothing new. One of the keys to Orbo is something that Thane also discovered -- namely, that there is a time lag in the response of the magnetic material (magnetic permeability). It was this asymmetry that allowed enough of a lag in the collapse of the mag-fld of the coil, that generated a PUSH against the PMs after they passed TDC, thus causing acceleration; and in some cases, going from 2200rpms to 2300, 2400, 2500, 2600 in one or two second intervals. Accelerating his large rotor 100rpms/sec is no small force. - One more thing that Thane discovered, and my explanation might be a bit off, was that one could 'reroute' the energy that would cause the BEMF by using the proper core material (low or hi permeability??? Can't remember), thus keeping that energy out of the air-gap (btwn PMs in rotor and stator coil/core) and off of the rotor. It is kept within the core material of the stator (and he had VERY large cores), routing it to the opposite pole of the adjacent PM; i.e., he provided a closed 'magnetic circuit'. In some work that I'm involved in right now, we are using permanent magnets and we have them mounted to a soft iron housing, which basically acts like a wire to route the magnetic flux/fld from the south pole of one set of magnets to the north side of the other set. If you don't do this, you've got mag-fld squishing out all over the place... Not a pretty site! :-) - Thane eventually discovered that his system required a tuning of the coils resistance and inductance to optimize the acceleration effect. At first he was using rather modest coil windings, but he ended up using a very high resistance coil (lots of turns of very fine wire) to take advantage of the time lag. He also ended up with some very hefty 'U' shaped cores whose open end width was the same as the spacing of the PMs on the rotor in order to provide a magnetic circuit in which to route the BEMF energy. As for the time lag of magnetic materials (domains), I don't know if Thane ever went as far as to explain it from a physics point of view, but I'll take a stab -- Electrons (elec currents) are much lighter than nuclei (magnetic moments), so electric currents can respond much faster than magnetic domains. Thus, if one designs the PM/EM/COIL systems properly, they can take advantage of that time lag and put it to good use. -Mark No virus found in this outgoing message. Checked by AVG - www.avg.com Version: 9.0.722 / Virus Database: 270.14.123/2592 - Release Date: 12/28/09 23:47:00
