Original poster: David Speck <dave@xxxxxxxxxxxxxxxx> Jim,Not to quibble too much with the comments of Mark and Leigh, but rotary three phase converters of your design are successfully used by a great many people to make usable three phase power out of single phase. I use a 10 HP converter to drive Yaskawa servo amps, which are very finicky about their three phase power input quality. Matt Whitman uses one to drive a 5 watt argon laser, and many machinists use them to drive all sorts of lathes, mills, and other devices for years on end without destroying them. I think Mark and Leigh are expressing concerns about static converters which try to make three phase current using only caps, but no motor. The effectiveness of these devices is considerably more limited than the rotary converter you propose. You may need to adjust the values of your run caps to balance the voltages on the three output phases under load. Granted that motor / generator sets are the gold standard, for the highest quality 3 phase production, but I'm confident that your rotary converter will work more than adequately for you TC system. I would not try to use a solid state Variable frequency drive unit to try to make three phase output. They has way too much twitchy silicon in them to handle the environment of a running TC power system, and I'd bet that they would most likely just shut down iv not presented with the expected inductive/reactive load. However, if all you are going to do is to rectify the resulting current, then I would think that there is little advantage in making three phase out of two, and then rectifying it to DC. ISTM that simply adding a larger filter capacitor to a single phase bridge rectifier should get you to the same place without the added losses of the rotary converter.
Dave ====+====+====+====+====+====+====+====+====+====+====+==== Tesla list wrote:
Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx> Jim: I have not been following this thread so pardon me if my comments are redundant. I believe that your "3 phase converter" is the type where you are using an idling motor(shown on your sketch) to allow one to drive a 3-phase motor. It is my understanding that this type of circuit will temporarily run a 3-phase motor up to a point somewhat below its 3-phase rating. It is also my understanding that the circuit loads(currents)will be seriously out of balance. As a result, it is not uncommon to eventually burn up the motor(not the idling one) when this circuit is used. Thus, I am not sure if it will drive your system the way you want since it is not really 3 phase power that you are developing. I had originally thought you were building something like a generator set where you were mechanically coupling a 1 phase motor to a 3-phase generator(motor), driving the 1 phase with 220VAC/1PH and thus actually generating 3-phase power from the 2nd motor/generator. Obviously, this is not the case, but this method would produce true 3-phase power. You might consult www.3phasepower.org. I believe they have extensive information on 1 phase to 3 phase conversion. Mark