Measuring the home current consumption

[Sceadwian]

L1 and L2 both provide 120 volts in relation to neutral, the phase relationship between L1 and L2 is 180 degrees. If you don't call that two phase you need your noggin examined. I don't care what's used commonly in electrical distribution that has no bearing on it being a cat, they just skin it a little different =) Technically you'd call it split phase but it's a whole lot of arguing over words. They only reason for the phase order requirement for it to be called polyphase is because of AC motor loads needing a fixed phase order. In a split phase supply an AC motor wouldn't know which direction to turn.

 

[tcmtech]

You apparently need to read up on your definitions of what single, two, and three phase power is and how its derived.

The wikipedia references for each are fairly accurate but a bit more simplified than my industrial power systems and applications book though. But they are still worth taking the time to read of course!

FYI I had to learn, and demonstrate how each phasing system works and can be interchanged for my electric motors and power systems labs and class work years ago when I got my Industrial Maintenance degree.

(I was an A++ student in my motors and power systems classes too)

I designed a high efficiency passive single to three phase converter system that allows standard unmodified three phase motors to be powered directly off of a standard single phase source while still maintaining their normal starting torque, full running power and while working at their rated efficiency levels too.
(Mainly just to prove some people wrong! The brownie points where just an added bonus.)

 

[Chippie]

Europe has pretty much a 230vac system even Australia...

I know the majority of your domestic appliance run off 110v, but some of the heavier gear runs off a 220v...

Any ideas why you have a 110v ac system over there?

 

[tcmtech]

Because we felt like it!

There are several versions of and reasons why we have it actually. A good on line search will likely bring up several of them.

 

[Chippie]

Because we felt like it!

QUOTE]

Yeah sure....

I'll have a read sometime when I get bored...

 

[Sceadwian]

I understand the basics of it a bit, I looked it up after your post. It still doesn't logically make any sense to me though. That's right up there with that whole arguement that we had about Ohm's law ages ago, about how the I=V/R etc.. equations aren't actually Ohm's law but just the equations derived from it. Ohm's law only actually applys to a very limited subset of materials under controlled environmental conditions, and it was real world experiements that got the data that was used to derive the equations, but the equations aren't Ohm's law =)

Once again I'll just have to say, I'm wrong, it's not a two phase system, it's a split single phase system. But that seems like a whole bunch of hullabaloo to go through over a minor technicality.

 

[tcmtech]

I understand. But its not like nitpicking never gets carried away around here though any way.

I had to learn the phasing terminology and descriptions once and continue to still use it so tend to try and point others towards understanding and using the more correct terms and definitions when I can.

If every one sticks with using the wrong terms and definitions it just makes everything that much harder to work with in general.

And FYI I did read the wikipedia information just to make sure I want using a wrong terms myself!
I even went looking for my old reference book today too. Now I am worried about where some of them went. I haven't seen it and a few others for a several years now as best as I can remember.
I hate loosing unique and practical reference books. They are so hard and often expensive to replace if copies can even be found.

 

[Sceadwian]

By the way TCM, my ears perked up a bit when you said you'd worked on a single to three phase converter, could you provide more info on that, and would it work with non-inductive loads?

 

[Chippie]

Sceadwian
All you ever wanted to know.......

**broken link removed**

 

[tcmtech]

Thats that old rotary to three phase conversion system. One motor is needed to get another motor going first. Its very inefficient and cumbersome.

I use a different approach. The units I make fit right on the side of the motor or very near by it thats doing the actual work and work directly with the main motor itself not separate from it.
Thats the part the so called phase converter experts seem to have an issue with. Apparently the components, values, and circuits I use are not supposed to work that way according to them. Demonstrations of actual in use applications be dammed! Its just not supposed to work that well or efficiently. There just not enough expensive and inefficient parts being used!

As far as working with non inductive loads it works great but an actual three phase motor does still need to be used to produce the actual three phase power for such loads at that point.
It works as a phase angle autotransformer of sorts if that makes any sense.
It uses the rotating motion of the rotor to create the needed phase shifting effects between the three sets of windings in order to get the balanced three phase output.

What I designed was first intended as a rotary drive system with direct mechanical output from the motor being the primary application.
However if you dont mind running a three phase motor as the phase generator and giving up a slight amount of system efficiency because of it it does work well as a true three phase power source!
Depending upon the size of the load and what type of loads, there are a few factors that require a set of PF capacitors values to be changed in order to keep the phase angles and voltages stable on the two generated legs.

I and several friends of mine have ran them for many years as power converters for industrial welders and other large three phase powered industrial equipment that needs a solid three phase source but only have single phase power available.

Thats more of the primary use of them as converter units. Everything else is just for allowing a cheap and often large (15 - 20 Hp) three phase motors to work effectively on single phase power sources.

Perhaps I will make a thread some time in regards to building your own! I have no problem sharing my formulas and circuits.

I however have issues with others trying to build their own and then using what ever parts and pieces they may have lying around (usually condition unknown) despite there being somewhat forgiving but still critical values of components that must be used per each application.
They usually mess it up once or twice and skip the test and tune all together and then blame me for it not working right or at all in their intended application.

Thats where I make my money. On the knowing how to tune them properly for the intended application.

 

[Chippie]

As far as working with non inductive loads it works great but an actual three phase motor does still need to be used to produce the actual three phase power for such loads at that point.
It works as a phase angle autotransformer of sorts if that makes any sense.
It uses the rotating motion of the rotor to create the needed phase shifting effects between the three sets of windings in order to get the balanced three phase output.

Yes I understand that part....

and the rest the you said regarding folk making their own and finding they dont work...

Its good to see we have so folk on here who know....

my esteemed tcmtech....