Can we stop calling it 220?

[Alchymist]

Charles E. Beck, needs to go back to school.

Have him answer the above question. 240V AC residential cannot exist without two phases.

Interesting. I guess all those welders and air compressors running off 240 without a neutral wont work then?

 

[MrMark]

Interesting. I guess all those welders and air compressors running off 240 without a neutral wont work then?

I made it very clear I didn't care how it was generated by the utility. I am focusing on the waveforms delivered to the user to use. Phases A and B are 180 degrees phase separated because they are inverted with respect to each other with respect to the center tap. There are two phases at the panel.

 

[theoldwizard1]

OK, if we are going to go that far with it...
Then why is the + end/post of a battery the hot side which has an excess of electrons meaning it has a Negative charge!

Alessandro Volta, creator of the first battery, postulated that "particles" of electricity flowed from one connection to the other. He had a 50-50 chance of getting it right, but he got it wrong ! Electron have a negative charge.

 

[theoldwizard1]

I'll change just as soon as the 2X4 is called by its real dim's.

I have seen a couple of house with real "2x4"s !

 

[theoldwizard1]

Can we please stop using the terms 110 and 220? Residential voltage in the USA has been 120/240 longer than I've been alive.

There is a lot of good information on Wikipedia

A distinction should be made between the voltage at the point of supply (nominal system voltage) and the voltage rating of the equipment (utilization voltage). Typically the utilization voltage is 3% to 5% lower than the nominal system voltage

Yeah, I know. 110 is not 95% of 120.

Can we stop calling it "single phase" too?

Or am I alone in believing it's 2 phases?

A split phase electricity distribution system is a 3-wire single-phase distribution system, commonly used in North America for single-family residential and light commercial applications. Its primary advantage is that it saves conductor material over a single ended single phase system while only requiring single phase on the supply side of the distribution transformer. Since there are two live conductors in the system, it is sometimes incorrectly referred to as "two-phase". The two live or "hot" conductors waveforms are offset by a half-cycle, or 180 degrees offset, when measured against the neutral wire. To avoid confusion with split-phase motor start applications, it is appropriate to call this power distribution system a 3-wire, single-phase, mid-point neutral system.

It is the AC equivalent of the original Edison 3-wire direct current system.

 

[Gooch]

Residential power is Single Phase. you have one winding on the primary side, one winding on the secondary side! someone tell me how i can get two phases with this. you create two legs when you center tap the secondary and create a neutral.

 

[rickairmedic]

I think the accepted delivery for 120/240 is +/- 10%. But 120/240 is still the best thing to call it.

For what it's worth, my Porsche engine is not really a boxer, in spite of its 180°-V architecture.

Ok Jack I'll play . You are right the engine in your porche isnt a boxer engine . The truth is not everyone knows the reason a " Boxer engine " is called a " Boxer " . They are called this due to the way the connecting rods work not due to their flat " box like " shape. With a Boxer engine one rod is moving out while the one next to it is moving in ( like a Boxer with the old one two punch ) . Hope this clarifies that . oh yeah 220/221 I agree whatever it takes .



Rick

 

[tdkkart]

Residential power is Single Phase. you have one winding on the primary side, one winding on the secondary side! someone tell me how i can get two phases with this. you create two legs when you center tap the secondary and create a neutral.

Stick a scope on the 2 legs and you will find 2 waveforms, 180* out of phase.

 

[Alchymist]

Try answering the question rather than responding with obfuscation. They work precisely becaue there are two phases. I am going to guess you can't answer the question or you would have already.

I made it very clear I didn't care how it was generated by the utility. I am focusing on the waveforms delivered to the user to use. Phases A and B are 180 degrees phase separated because they are inverted with respect to each other with respect to the center tap. There are two phases at the panel. You would not get 240V AC from connecting across two phase wires without two phases at the panel.

OK, A 240 volt load not utilizing a neutral- when you look at the wave form, what do you choose as a reference? Obviously it has to be one hot line or the other. An oscilloscope referenced to one side and displaying the waveform on the other hot lead will show a sine wave- . There is nothing else to compare the displayed sinewave to, since the other hot is the reference. So, where is the second phase?

Splitting the secondary of a transformer for a neutral does not make it a two phase system. Look at it this way - a three phase transformer requires 3 coils, a single phase system requires one.

 

[tdkkart]

I am focusing on the waveforms delivered to the user to use. Phases A and B are 180 degrees phase separated because they are inverted with respect to each other with respect to the center tap. There are two phases at the panel. You would not get 240V AC from connecting across two phase wires without two phases at the panel.

Absolutely correct............

 

[Berserker]

But its created with a single phase, you get two by cutting it in half. But the primary voltage is single phase.

Your wife has twins, does that mean you screwed her twice?

 

[Alchymist]

Stick a scope on the 2 legs and you will find 2 waveforms, 180* out of phase.

One waveform - you are just choosing an "artificial reference". See previous post.You are merely displaying one end of the secondary winding going negative while the other end goes positive.

 

[Alchymist]

NEC must have it wrong also when they specify "NEC minimum is 100A, single phase, 3 wire for a single family dwelling unit service.

 

[Berserker]

Don't tell the inspector the NEC is wrong.

 

[ibedayank]

OK, if we are going to go that far with it...
Then why is the + end/post of a battery the hot side which has an excess of electrons meaning it has a Negative charge! (I know the real answer, but it still confuses the heck out of high school physics students every year!)

well i still work on stuff that DOES have positive ground...lol

 

[Berserker]

You could have a grounded B phase. Utility decides what it wants to ground, or did at one time.

First time I came across grounded B phase kicked my ***.

 

[NukleoN]

I remember Price Club. I would also prefer to call my electricity voltage by what it is...if I only knew LOL.

 

[MrMark]

One waveform - you are just choosing an "artificial reference". See previous post.You are merely displaying one end of the secondary winding going negative while the other end goes positive.

Which is exactly what you are doing in your panel. One side is between the "positive" side of the transformer and the neutral reference and the other side is between the negative side of the secondard and the neutral reference. Just because the utility generates a single phase doesn't mean that you can't generate two phases downstream. The scope sees the same waveforms that the separate sides of your panel see. Calling it "single phase" is just arbitrary terminology that focuses on the generation side. If it were really single phase at the panel, we wouldn't refer to Phase A and Phase B and we wouldn't have MWBC.

 

[Hurricane_Whisperer]

Ok, single phase it is.

How about "3-way switches". I think they are 2-way switches; it either throws the power this way, or that way.

Anybody with me on that one?

You forgot about off.

It's a three way switch.

 

[Norcal]

Charles E. Beck, needs to go back to school.

Have him answer the above question. 240V AC residential cannot exist without two phases.

Explain SWER ,Single Wire Earth Return, used for HV single phase primaries, by some PoCo's & in other countries, there is a single HV conductor supplying the ****** w/ a earth return.

There single phase, some legacy 2 phase still in service in Philadelphia & other cities from the early days of electricity, and 3 phase.

 

[Hurricane_Whisperer]

not alone
I agree

110/120 single phase
220/230 2 phase
and then there is the 3ph that has several voltages to choose from

bob

That's totally wrong.

Residential is almost all single phase power. You can have 120 single phase and 240 single phase.

3 phase power is completely different, has nothing to do with voltage and is used in industrial applications. The phase refers to the sinusoidal phase of the power on the various legs. Electric motors will be specifically made to run on 3 phase power. The voltage may be 230 or 460.

 

[MrMark]

I thought you were a mechanical engineer focusing on bolt stretch?

Electricity is complicated business and the EE's don't even really understand it.

 

[Nick M]

That's totally wrong.

Residential is almost all single phase power. You can have 120 single phase and 240 single phase.

3 phase power is completely different, has nothing to do with voltage and is used in industrial applications. The phase refers to the sinusoidal phase of the power on the various legs. Electric motors will be specifically made to run on 3 phase power. The voltage may be 230 or 460.

Don't forget about 550v.

 

[joemh22]

I thought you were a mechanical engineer focusing on bolt stretch?

Electricity is complicated business and the EE's don't even really understand it.

How do they not understand it?

 

[electrican]

220 single phase!

 

[Hurricane_Whisperer]

Charles E. Beck, needs to go back to school.

Have him answer the above question. 240V AC residential cannot exist without two phases.

The electric motor that powers the compressor on the vast majority residential central air conditioners is a 230V, single phase.

Good luck finding a "2 phase", 230V, electric motor.

 

[Steve from Socal]

This is exactly why Edison hated Alternating Current!

Steve

243 volts of something here in DWP land

 

[Alchymist]

Here ya go:

http://en.wikipedia.org/wiki/Two-phase_electric_power

http://www.ccontrolsys.com/w/Two_Phase_Electrical_Service

Take yer pick!

 

[MrMark]

Like I said, it is all definitional. The single phase refers to the generation equipment. Probably to distinguish it from older two phase generation systems. Ignoring the inverted waveforms referenced from the neutral in a split wire system and calling it single phase is a mistake. The neutral reference compels that result.

As to the EE's, because they are smart enough to know that no one fully understands electricity.

 

[MrMark]

Here ya go:

http://en.wikipedia.org/wiki/Two-phase_electric_power

http://www.ccontrolsys.com/w/Two_Phase_Electrical_Service

Take yer pick!

I'll look at this later, this is a pretty complicated subject, but pretty interesting too.

 

[Berserker]

LThe single phase refers to the generation equipment.

You get 240 single phase from one phase of primary at the distribution level. One of three phases makes 240.

 

[MrMark]

I just glanced at yer second link there and you better try again. That link is not correct technically, and even contradictory. The phases are not 120 degrees out, they are 180 degrees apart because they are inverted.

 

[Hurricane_Whisperer]

Try answering the question rather than responding with obfuscation. They work precisely becaue there are two phases. I am going to guess you can't answer the question or you would have already.

I made it very clear I didn't care how it was generated by the utility. I am focusing on the waveforms delivered to the user to use. Phases A and B are 180 degrees phase separated because they are inverted with respect to each other with respect to the center tap. There are two phases at the panel. You would not get 240V AC from connecting across two phase wires without two phases at the panel.

It doesn't matter whether you care or not, the fact is there is is only one phase of power being supplied. The neutral is wired to the center of the transformer. The two "phases" are the same, hence the term single phase.

There are many low power single phase air compressors that come wired for 120V and they can often be wired for 230V, single phase, because this just means the amp draw is less.

3 phase power has three legs where the amplitudes are 120 Degrees out of phase with another.

 

[Alchymist]

I just glanced at yer second link there and you better try again. That link is not correct technically, and even contradictory. The phases are not 120 degrees out, they are 180 degrees apart because they are inverted.

I think they were referring to the 120 deg phase between the transformers hung off each leg of the three phase system, which would, in fact, be 120 deg. Could have been worded better. In fact, if you have three houses each with a transformer on a different leg of the three phase supply, the single phase power in each house will be out of phase with their neighbor by 120 deg.

 

[Hurricane_Whisperer]

Explain SWER ,Single Wire Earth Return, used for HV single phase primaries, by some PoCo's & in other countries, there is a single HV conductor supplying the ****** w/ a earth return.

There single phase, some legacy 2 phase still in service in Philadelphia & other cities from the early days of electricity, and 3 phase.

And there is the answer. There was actual 2 phase power a long time ago and apparently still in Philadelphia.

Everywhere else in residential power, it is single phase.

 

[Hurricane_Whisperer]

I thought you were a mechanical engineer focusing on bolt stretch?

Electricity is complicated business and the EE's don't even really understand it.

Yes, that's why they have lawyers explain it to them.

Because if you can't learn how things actually work, you can always argue based on your misunderstanding of what an article says due to a complete lack of knowledge of the fundamentals.

 

[Hurricane_Whisperer]

Like I said, it is all definitional. The single phase refers to the generation equipment. Probably to distinguish it from older two phase generation systems. Ignoring the inverted waveforms referenced from the neutral in a split wire system and calling it single phase is a mistake. The neutral reference compels that result.

As to the EE's, because they are smart enough to know that no one fully understands electricity.

Utilities generate three phase power.

They send three phases of power to your neighborhood.

When they distribute the power to your neighborhood, they send one phase to a group of homes, another phase to another group of homes and the last phase to another group of homes.

That is why you have single phase power.

 

[Gooch]

this is why i hate engineers, they make things seem more complicated than they actually are.

 

[Hurricane_Whisperer]

Like I said, it is all definitional. The single phase refers to the generation equipment. Probably to distinguish it from older two phase generation systems. Ignoring the inverted waveforms referenced from the neutral in a split wire system and calling it single phase is a mistake. The neutral reference compels that result.

As to the EE's, because they are smart enough to know that no one fully understands electricity.

Here's how easy this is to understand.

There are three wires on the transmission lines on the poles in my back yard. These are the three phases being transmitted by the power company.

There is a single wire connected from one of the three transmission wires to the transformer that steps the transmission power down to my house. One wire goes into the transformer from the transmission lines. There is only one transformer. Coming out of the transformer are three taps. Since my service is so close to the transformer, the three wires come directly to my service entrance. (They also connect to the three wires that distribute the stepped down power to the other houses.)

Since only one wire goes into the transformer and that transformer provides all of the power to my house, the power is single phase. If I had three phase power, there would be wires coming from a transformer on each of the other two transmission wires.

The difference in voltage is the difference in the location of the tap with respect to the transformer coils.

 

[MrMark]

Yes, that's why they have lawyers explain it to them.

Because if you can't learn how things actually work, you can always argue based on your misunderstanding of what an article says due to a complete lack of knowledge of the fundamentals.

You were embarrassed by that tour de force. That article said exactly what I said it said, it was not subject to reasonable dispute. I'm not just a lawyer.