Electronics > Projects, Designs, and Technical Stuff
Single phase to three phase sinewave converter
soldar:
It is interesting to know how many of the standards we have today are the product of evolution. You can pick any standard device and think it is badly designed. British plugs, NEMA, Schucko, all have their cons and maybe you can find something if their favor but they all emerged like that for their own reasons. One thing I do not like about Schucko is that it is not polarized but the Wikipedia explains why. I also don't quite like the Earth contact system.
At any rate, in Italy they used to have different rates for lighting (luce) and for motor power (forza) and they had different plugs. Of course one of the most common items was a plug converter which allowed using cheap electricity for lighting. https://en.wikipedia.org/wiki/File:ForzaLuce1950.jpg
Even though I have never seen it personally it used to be the same in Spain and a carryover from all that is that, even though today they are connected to the same meter and pay the same rate, circuits are either for "lighting" (luz) or for "power" (fuerza) and those circuits have different requirements. Lighting does not require protective earth while power does. I find it stupid. And also, as a carryover from those old times a thingy which allows three plugs into one socket is called an "electric thief", just like in Italy. You can search Google images for -ladrĂ³n electricidad- (electricity thief) and see what I mean.
I have a theory that the design of the BS plug was so big so that it could be used as a boat anchor in an emergency. ;)
soldar:
Getting back to the OP, it would not be too difficult to design a three phase signal generator, even of variable frequency, followed by three linear audio amplifiers. I think this would be an interesting project.
This might practical up to, say, 50 or 60 W per channel. Once yo get into some real power the linear amps are going to be dissipating some real heat and a switching amp would make more sense.
I can't see a real need for a low power three phase source but it would be an interesting project.
capt bullshot:
--- Quote from: soldar on January 15, 2019, 04:11:17 pm ---
Let us rewind for a moment. The OP needs very low power three phase supply for some tests or experiments. Someone says he would not have to deal with such "garbage" if he were in Europe where pretty much all households have 3 phase supply. I say that is not so except in the sense that pretty much all households own a Learjet. Yes, if you have the money you can get one but you do not have one now ready to go and you do not have three phase supply ready for me to come over and plug in my three phase motor.
--- End quote ---
I don't own a Learjet, but just because I don't have enough space to build the appropriate hangar on my property ;)
So this is the panel in the basement, and the three-phase outlet in the basement. There's another one in the garage. The cooker / oven in the kitchen has a three-phase feed. It's been there when I bought that house, so no excuses I might have installed that just because I've wanted that. Anyway, if I would walk (I won't do that) to a random neighbor and ask him to show me his / her panel, it would be a three-phase installation like mine. Mine's quite a modern one, with an additional (single phase) meter for the solar installation, but older ones look similar, often you find a mechanical (Ferraris wheel type) three-phase meter. Very old ones have a single phase meter, but a three-phase feed available at the panel, one just has to ask the utility to replace the meter. There's no single phase distribution here at all. Even in e.g. a two-room rented flat it's normal to have three phase power at the breaker panel with a three-phase meter installed.
Other countries have other standards, for sure.
Edit: added a random (images search found) picture of a typical (old style) household distribution line (four wires, three phase). You won't find these anymore since they buried the cables under the streets in large scale some ten years ago.
MrAl:
Hello again,
Quick note...
Around this area we mostly see 3 phase power systems in industry.
Yeah i think anyone can get it but it will cost much more than a standard home bi phase service (USA).
soldar:
--- Quote from: capt bullshot on January 15, 2019, 06:59:33 pm --- So this is the panel in the basement, and the three-phase outlet in the basement. There's another one in the garage. The cooker / oven in the kitchen has a three-phase feed. It's been there when I bought that house, so no excuses I might have installed that just because I've wanted that. Anyway, if I would walk (I won't do that) to a random neighbor and ask him to show me his / her panel, it would be a three-phase installation like mine. Mine's quite a modern one, with an additional (single phase) meter for the solar installation, but older ones look similar, often you find a mechanical (Ferraris wheel type) three-phase meter. Very old ones have a single phase meter, but a three-phase feed available at the panel, one just has to ask the utility to replace the meter. There's no single phase distribution here at all. Even in e.g. a two-room rented flat it's normal to have three phase power at the breaker panel with a three-phase meter installed.
--- End quote ---
OK, this is interesting. I can't see the photos well so I will just take your word for it. Is this general use in all of Germany? Even what used to be Eastern Germany? What is the amperage or power available at the panel? Is the range/stove water heater or other appliances three phase? It would be interesting because I have never seen three phase appliances sold here. Part of it is that we have very expensive electric rates and using gas or other fuel is cheaper.
I mean, if they wanted they could build every home here with the panel already prepared and wired for three phase but it saves a little money at building time and it means a lot more cost to retrofit. Like so many other things. I would like to have cat5 ethernet cable in every room but it would cost me a fortune now to install when it could have been done at new construction for very little.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version