More Phases for more Conservation

I work with it all: ac power, dc power, single phase, three phase, split phase… heck as I showed a member on her recently, in 300 feet we go from 125 volts dc power to 34,500 volts ac power…

But what if a home went with higher phases? It would have to be in factors of three, but if 3 phase is better than sex, then what would six, twelve and 24 phases do? Aside from the added costs of 6/12/24 switching gear, there is conceivably some efficiencies gained.

What would that look like? A home self powered at say 12 phase then split down to 3 or single phase from the grid?

It could be a little more efficient, but I believe three phases is where most consider the point of diminishing returns. Looking at a single phase sine wave, it is clear where there are inefficiencies, even zero power at points. It looks like with three phase, the power never drops below half. It would always need to be an odd number apparently, since having any phases 180 degrees apart would reduce the efficiency (assuming equal spacing). Someone better at math than I could probably easily figure out how much more efficiency each phase could deliver. Three is enough to naturally spin an induction motor as well.

At least for off-grid production, you can make three-phase, but at a cost of having three individual inverters, which of course means three times the cost.  So, as Jordan outlines, it's the point of diminishing returns.  Adding more and more complexity basically means adding more and more that can wrong.

Michael Qulek wrote:At least for off-grid production, you can make three-phase, but at a cost of having three individual inverters, which of course means three times the cost.

I think that is a valid argument for three phase power and solar, but I am not sure it is valid for multiple phases like 6, 12, or 24 phase systems that use synchronous generation. That is because you cannot buy polyphase units in turnkey units, so they would have to be produced. That is easily done inside the generator stator and field windings, so no inverters needed since it is making 12 phase at the point of generation.

But at the same time, let's say someone did invest in 12 inverters to make 12 phase solar power, they would also be taking what they are making for solar power, and converting more sunlight into usable work. At some point it is a diminishing return since phase angles are squared and not simply divided, but that does not factor in extra losses that single and three phase power has. Those losses also add up over the lifetime of the generating system.

Here is an example; I always use 12-gauge conductors to wire my houses because in 6 months' time, the resistance losses are so much less than 14 gauge conductors, that it pays for the bigger 12 gauge wire. 10 gauge wire is even better... so why don't I use it? It is not the cost; it is trying to finagle 10 gauge conductors in electrical boxes and on standard outlets that makes it very difficult. The cost is nothing because I can recover that in 3 months time.

I would think it would be the same with three phase power for solar even. While it would mean buying three inverters, you are gaining usable energy from the amount of light hitting your collectors. Even more so from poly-phase systems.

Which kind of brings me full circle, if we use car alternators that produce 3 phase ac power and rectify it down to 12 volts dc because that is the most efficient way to charge our batteries, why aren't we making poly-phase stems for synchronous home electrical production? I can see the high cost of long distance conduction of electricity on the grid, but surely we could be making more power, with less total hormonic distortion at the point of production for home-based systems for every gallon of gas, cubic feet of water, or wind energy consumed.