May I ask a question about the single vs two phase stuff

[Besoeker]

However, a six-rectifier 3ph supply could be called either six half-wave or three full-wave, which is what I meant.

Full wave it is not. Full wave uses both half of the cycle. Half wave uses just the positive half. That's what hexaphase does.

Another way to look at it. A full wave bridge conducts through two semiconductors at the same time on each cycle. Half wave conducts through just one. The application normally determines which arrangement is most suitable. For high current, low voltage rectifiers half wave is often the better way to go. It doesn't make best use use of the transformer capability but the forward loss for the semiconductors is for one device at a time.

Also, back in history when semiconductors were expensive, half wave reduced the component count.

 

[Sahib]

Hexaphase is centre tapped three phase - looks like a wheel with six spokes. If that's hex, why isn't 120-0-120 two phase or maybe biphase?

If you refer to technical literature, 240/120V or 120-0-120V is called single phase AC source. But you are free to call it as you like.

 

[Besoeker]

If you refer to technical literature, 240/120V or 120-0-120V is called single phase AC source. But you are free to call it as you like.

At the risk of repeating this ad nauseum, the two 120V outputs are in anti-phase i.e. not the same phase. Whatever you want to call it.

 

[Sahib]

At the risk of repeating this ad nauseum, the two 120V outputs are in anti-phase i.e. not the same phase. Whatever you want to call it.

They are not in phase but 180 degree out of phase. But still it is called by Engineering community as single phase supply. You may show how the change you propose is beneficial for adoption by the Engineering community as a whole.

 

[jaggedben]

<sigh>

 

[Besoeker]

They are not in phase but 180 degree out of phase.

That was the point I made. Glad to have your erudite corroboration.

But still it is called by Engineering community as single phase supply. You may show how the change you propose is beneficial for adoption by the Engineering community as a whole.

I'm not proposing any changes and I don't see how you could construe that from what I have posted.
It just is what it is.

 

[Sahib]

That was the point I made. Glad to have your erudite corroboration.


I'm not proposing any changes and I don't see how you could construe that from what I have posted.
It just is what it is.

So you agree 240/120V is a single phase AC source per terminology adopted by Engineering community?

 

[Besoeker]

So you agree 240/120V is a single phase AC source per terminology adopted by Engineering community?

The terminology is what it is.
Can we leave it at that pretty please?

 

[Sahib]

Mods, may this thread be closed please?

 

[ggunn]

At the risk of repeating this ad nauseum...

At nearly 1100 posts wrangling over the same silly argument it is far, far too late for that.

 

[Besoeker]

At nearly 1100 posts wrangling over the same silly argument it is far, far too late for that.

OK.

 

[mivey]

Hexaphase is centre tapped three phase - looks like a wheel with six spokes. If that's hex, why isn't 120-0-120 two phase or maybe biphase?

Because most people don"t use it that way and most are familiar with circuits that use a single phase.

Pulse circuits, as you have pointed out, and some rectifier circuits use a positive pulse/signal at 0 degrees and a positive pulse/signal at 180 degrees. It is this case where we can use the center-tapped winding to provide signals with a 180 degree difference rather than using two 180 degree displaced generator windings.

But we have covered that before. There can be two phases present but the name assigned is single-phase. The two-phase name is reserved for quadrature displacement.

As we have also covered, names and physical characteristics don't always match, for tgis and other configurations as well.

 

[mivey]

If you refer to technical literature, 240/120V or 120-0-120V is called single phase AC source. But you are free to call it as you like.

No one has suggested a name change. Only you have done that.

 

[mivey]

At nearly 1100 posts wrangling over the same silly argument it is far, far too late for that.

No doubt.

 

[Fulthrotl]

Mods, may this thread be closed please?

ohoh. someone tapped out.

 

[Fulthrotl]

Careful - this topic is probably more likely to end up closed than a topic with "gun" in the title. :lol:

how little faith. your's was the second post.

 

[Sahib]

No one has suggested a name change.

Then what is the point of this thread?

 

[LarryFine]

Then what is the point of this thread?

You should know by now: The more pointless the topic, the longer the thread.

 

[mivey]

Then what is the point of this thread?

Read post #1. There seems to be a question to some of is there a 180 degree difference present.

My point is you can take two equal magnitude voltages in phase or two equal magnitude voltages with a 180 degree displacement away from a center tapped transformer. It is a fundamental concept that to define a voltage you can pick any reference point you want. You can pick the end of the winding or the center but it is up to you.

That some people don't get that the reference can be away from center is interesting to me. You can try to talk through it but if someone disagrees with that then you really go nowhere because that is just simple physics and not really a debate. Not much to discuss really other than try to help someone understand.

But that is not the part that causes most of the discussion.

Fundamentals aside, the fun with phases begins when you look at the definition of phase. Depending on the definition used, you can say there is one phase or you can say there are two phases. Both are valid because both definitions are valid in there own right.

To me, the error is to dismiss one or the other. I support both definitions.

 

[mivey]

You should know by now: The more pointless the topic, the longer the thread.

The curse of the bored.