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

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buffalonymann said:
I know what it is, typically used for control transformers - my comments regarding single phase transformers pertain to one coil that is centertapped
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All wound together on a common core but with the center leads brought out it gets classed as a multiwinding transformer.
 
readydave8 said:
yes blocked

almost didn't click because thought it was power-bridge thread

but now that I'm not allowed to view it, I really want to
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It is too cumbersome and disorganized. A lot of good info buried in there but too much bickering. I offered to clean it up but there were too many hurt feelings for that to happen.

I have almost all of it saved and thought of posting a scrubbed version outside the forum but I really have minimal interest. I never look at it because it is very hard to trace all the side conversations and paths and is not entertaining due to the amount of fussing.

I had several hundred posts and got caught up in the bickering as did most of the main contributors. Not our best moment on the forum.
 
roger said:
Ok, it was put in the vault due to a lot of bickering and insults being slung so that is where it will remain. With that being the case, let's keep this one from being closed or removed for the same reason.

Thanks

Roger
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Hear! Hear! The snarkiness takes all the fun out of it.
 
buffalonymann said:
Current is the work performed. Canceled current means canceled work. Canceled currents would also mean no money for power company.
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current is not the work performed. cancelled current means the sine waves are added together on the neutral and the result is zero.

buffalonymann said:
Ummm (E)(I)=P therefore current is work :cool:
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E*I = S. E*I*cos (pf) = P. the equation you provided does not prove current is work.

buffalonymann said:
Would you just try to think of what current actually is; its clearly the work that's being performed.
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how is current the work being performed? work is power per unit time. current is most certainly proportional to work, if that's what you are meaning to say.

buffalonymann said:
when you have two equal loads across l1-n and l2-n you've created a series circuit and the current is found on l1 and l2.
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a series circuit isn't "created" by having balanced loads on l1-n and l2-n. there are two current phasors that meet at the neutral and add (KCL) on the path back to the center tap. when you add the current phasors and the loads are equal, they cancel because they are 180 degrees out of phase with one another and the same magnitude. the moment you have imbalanced load, the difference in magnitude will appear on the neutral.

buffalonymann said:
current is not a magnetic field
current is the resultant work performed due to emf
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magnetic fields are created due to movement of charge.

current is the movement of electrons in response to an electric field. work is power per unit time.

buffalonymann said:
Yeah, and it's flowing because work is being done;)
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current is flowing because the electrons forming a continuous path were subjected to an electric field. the work done depends on the current and voltage together.

let me ask the forum a question.

what if i operate a low power factor load on one leg of a split phase transformer while keeping the other leg purely resistive? how does this impact the magnetic field within the first and second halves of the secondary winding, if at all? will there be an measurable response in the opposite winding?

the current on l1-n will experience a phase shift. the current on l2-n will not. two phasors.
 
drktmplr12 said:
let me ask the forum a question.

what if i operate a low power factor load on one leg of a split phase transformer while keeping the other leg purely resistive? how does this impact the magnetic field within the first and second halves of the secondary winding, if at all? will there be an measurable response in the opposite winding?

the current on l1-n will experience a phase shift. the current on l2-n will not. two phasors.
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you mean like this?
http://forums.mikeholt.com/showthread.php?t=192670&page=31&p=1931467#post1931467
 
drktmplr12 said:
...
let me ask the forum a question.

what if i operate a low power factor load on one leg of a split phase transformer while keeping the other leg purely resistive? how does this impact the magnetic field within the first and second halves of the secondary winding, if at all? will there be an measurable response in the opposite winding?

the current on l1-n will experience a phase shift. the current on l2-n will not. two phasors.
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If I'm looking at the two current waveforms, and I want to know how much instantaneous current is flowing on the neutral at a given point in time, do I need to use phasor math or can I just use simple subtraction?

Or, for a more practical take on the question: If I'm hooking up unbalanced loads or sources to a split-phase system, based on maximum nameplate currents of the equipment, do I need to know any phasor math to size my conductors correctly? Or can I do it with elementary-school-level addition and subtraction?
 
It requires phasor math if loads are anything other than resistive. If you can calculate the hypotenuse of a triangle you can do phasor math.

Sent from my Pixel 2 using Tapatalk
 
So let’s say my goal is to create a -1 reproduction of a complex wave form ( music).

If I wish to use passive devices I could use a center tapped transformer, center tapped choke, or center tapped auto transformer. Are there other choices? If I’m looking for greatest bandwidth, linearity, and constant Z....which is the best choice?
 
jaggedben said:
If I'm looking at the two current waveforms, and I want to know how much instantaneous current is flowing on the neutral at a given point in time, do I need to use phasor math or can I just use simple subtraction?

Or, for a more practical take on the question: If I'm hooking up unbalanced loads or sources to a split-phase system, based on maximum nameplate currents of the equipment, do I need to know any phasor math to size my conductors correctly? Or can I do it with elementary-school-level addition and subtraction?
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it can be shown mathematically the neut will always be less than or equal to the largest line current
if they differ it will be between them, closer to the larger
if you use a full size neut you are good UNLESS the devices are non-linear and have high thd

someone posted an algebraic equation to calculate it
3 ph equation
just leave C out for 3W
http://forums.mikeholt.com/showthread.php?t=144531&p=1390895#post1390895

should work, have crunched the numbers for a 120/240/1 ckt
 
mivey said:
It is too cumbersome and disorganized. A lot of good info buried in there but too much bickering. I offered to clean it up but there were too many hurt feelings for that to happen.

I have almost all of it saved and thought of posting a scrubbed version outside the forum but I really have minimal interest. I never look at it because it is very hard to trace all the side conversations and paths and is not entertaining due to the amount of fussing.

I had several hundred posts and got caught up in the bickering as did most of the main contributors. Not our best moment on the forum.
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Please do not post that thread or what you have of it.

Nobody, definitely including me personally, came of that quagmire completely clean.:ashamed1:
 
jumper said:
Please do not post that thread or what you have of it.

Nobody, definitely including me personally, came of that quagmire completely clean.:ashamed1:
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Yes, our behavior was quite embarrasing. You weren't modding at the time but even the mods got in on the bad behavior. Best forgotten as many hurtful words were exchanged and no need to expose old wounds.
 
buffalonymann said:
we'll have to agree to disagree on this
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Disagree if you like but that is how it is with utility distribution transformers.

Dual leads are brought out and the windings can be connected in series or parallel. So even if you wanted to make a weak case on tap terminology for a single lead, that is not what we have.

Some links that may help you understand:

https://www.electronics-tutorials.ws/transformer/multiple-winding-transformers.html

http://www.idc-online.com/technical...engineering/Multiple_Winding_Transformers.pdf
 
mivey said:
Disagree if you like but that is how it is with utility distribution transformers.

Dual leads are brought out and the windings can be connected in series or parallel. So even if you wanted to make a weak case on tap terminology for a single lead, that is not what we have.

Some links that may help you understand:

https://www.electronics-tutorials.ws/transformer/multiple-winding-transformers.html

http://www.idc-online.com/technical...engineering/Multiple_Winding_Transformers.pdf
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First, thanks for those links, Mivey. Great training material.

Second some things I have learned from being here all these years:

If GAR or Mivey are trying to tell you something it is best to listen, because they know.

A very esteemed member here taught me this years ago.
The general formula to determine the number of phases in any system is: 360 degrees divided by the angular displacement between the phases equals the number of phases in that system.

360/120=3phases
360/180=2phases
360/360=1phase
360/90=4phases, but since only half of the system was needed & used it became misnamed two phase. An is still causing much confusion to this date.

The beauty of a real 2 phase system is that with an angular displacement of 180 degrees the math stays on the real number line, at least for resistive loads or adding the voltages between coils.
 
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