Suppose you wanted to run an irrigation system that requires three phase, 480 to operate. Suppose the local rural power company could only supply you with single phase 480. Suppose Emma Genius then built a rotary phase converter to make that three phase load run from single phase. Suppose that rotary phase converter created only the third leg of the three phase to operate the three phase load. Where did the other two necessary phases originate to operate that three phase load?
I'm still waiting for one of the "experts" to give us their definition of phase. They've been talking about it for a week now, but not one will define it.
I'm also waiting for a response to the two phase student excercise I posted earlier. They all seem to agree that two phase existed
100 years ago. They have no problem with it being called two phase, that was the only legitimat two phase according to them. So, that system had two phases, let's call them A and B and a neutral. Phase B was 90 deg off from phase A. Everyone OK so far?Now, instead of having phase B be off by 90 degrees, let's make it off by 120 deg. How many phases are there now? I say two. Let's change it again, so phase B is off by 220 degrees. How many phases do we have now? I say two. Let's change it to being off by 170 deg, how many phases do we have now? I say two. And now, let's change it to be off by 180 deg. How many phases do we have now? I say two. And if it they agree that it is indeed still two, then it is in fact electrically identical to split-phase 240/120V service, so you have two phases there too.
QED
You do sin/cos/tan functions by hand? ;-)
I've only taken one trig class - 8 weeks (half a semester) in high school. They used the "unit circle" method, which was quite a good method of teaching. Understanding is much easier then mindless memorization and lasts longer.
It's quite simple. The rotary phase converter is a generator.
All you are doing is reversing the leads on your scope to get a fake second phase. Your cheap trick will only fool an imbecile.
I don't know about you and Emma but I'd send that piece-of-shit rotary phase converter back to China Harbor Fright and get a proper one from
Complete inability to address the simple and carefully outlined learning excercise I gave, noted. Inability to even define the term "phase", as requested noted. As is the name calling which is what you're left with when you don't have engineering or the facts on your side. And for the record, a scope wasn't even involved.
I can't remember whether my old Hughes Owens slide rule had trig functions on it or not. It seems to me that it didn't.
Back before there were calculators, engineers would carry around a book called the CRC Handbook, published by the Chemical Rubber Company, whoever that was. That book had tables for squares, square roots, cubes, cube roots, trig functions, hyperbolic trig fuctions, etc. You would use those tables to find the values of trig functions if you knew the angle expressed in degrees or radians.
No one ever worked out trig functions by hand, although you could do it. There were Taylor series solutions developed for all the trig functions, and the computers of the time used those series approximations to generate sine, cosine, and tangent. For example, the Taylor series for exponential of x, sine of x and cosine of x are:
exp(x) = 1 + x + x2/2! + x3/3! + x4/4! + ...
sin(x) = x - x3/3! + x5/5! - x7/7! + x9/9! - ...
cos(x) = 1 - x2/2! + x4/4! - x6/6! + x8/8! - ...
where x3 means x cubed, or X times X times X, and the exclamation mark means "factorial". for example: 8! = 8 X 7 X 6 X 5 X 4 X 3 X 2 X 1 =
40320So, you can do trig functions by hand, but the way you do them lends itself better to computer calculation.
I need a new furnace. Are two phase furnaces more efficient and where can I get one?
Again, complete avoidance of the intellectual excercise on phase I outlined above noted. No answer to the simple question of giving a definition of the engineering term "phase" noted. Smart remarks don't build a case.
I can define it. And I'm still waiting for an answer why a system with two phases that differ by 90 deg is acknowledged by everyone to have two phases. If they differ by 240 deg, that's two phase right? If they differ by 170 deg, that must be two phases, right? So, what magically happens when they differ by 180 deg that suddenly there are no longer two phases? And how do the electrons know?
For a garden variety split-phase supply (240/120V from a transformer with a centertap) are there 2 "phases"?
Non-response to the simple thought excercise on phase, going from what everyone agrees is two phase, to what is electrically identical to the 240/120V split-phase service. Non-response to repeated requests for anyone on the other side of this to define the term "phase". How can you talk about it, yet not one of you can define it?
As to your question, IDK why you're asking. My answer is clear and has been discused at length. The answer is Yes. The author of the engineering paper presented at the IEEE conference of power engineers agrees. As do the several white papers/app notes from electrical eqpt manufacturers, etc. that I've cited as well.
In maths/physics, you have two phases with a mathematical relationship of -x (or a 180 deg phase shift).
In electrical distribution, two-phase is a specific jargon term which means something else.
There's no one right answer - it depends on the context of the discussion.
My Versalog did. My HP45 did, too. ;-)
The Chemical Rubber Company, of course. ;-)
No, most people who needed such things carried a slipstick. The tables were needed only in the *very* few cases where extreme accuracy was needed. The damned CRC Handbook must have weighed 5 pounds. No one "carried it around".
No shit?
You want an oil furnace. The furnace changes the oil form the liquid to the gaseous phase. I suppose you could use a boiler, too, but that's not a "furnace". ;-)
A cheap slide rule I have has the sin and tangant trig functions on it. The wider the rule, usually the more functions on it.
I had a CRC book but it was not a 5 pounder. Just small text book size. Not sure if it was the whole book or just a book with part of the CRC book in it.
I remember seeing some films with a room full of engineeers with slide rules that were shown as desiging the SR71 Blackbird.
Did you know that the SR71 Blackbird was originally intended to be called the RS71 Blackbird. But, when President Johnson (I think it was) held a briefing to explain the project to some Senators that controlled the purse strings on black projects, he repeatedly called it the SR71 instead of the RS71.
So, they quickly changed the name of the plane from RS71 to SR71.
The context is, specifically, in US power distribution is a split-phase supply called 2 phase with a phase A and phase B.
(Not "2-phase", which as you say is rather different.)
I don't think you have much split-phase over the pond. If I remember right, construction sites may have 120/60V circuits.
I have a gas furnace. Can you get 2-phase gas?
Only when the centertap is your reference point.
Maybe a 240V-only appliance (no neutral) is adding to the confusion?
I've seen a cable that gets 120V/240V form two small generators (which each produce only 120V). Do you think that makes a difference in how many phases you have?
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