Speaking of electricity.............

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~In Brazil there is no standard voltage. Most states use 127 V electricity (Acre, Amapá, Amazonas, Espírito Santo, Mato Grosso do Sul, Maranhão, Pará, Paraná, Rondônia, Roraima, Sergipe and Minas Gerais). Other – mainly northeastern – states are on 220 V (Alagoas, Brasília, Ceará, Mato Grosso, Goiás, Paraíba, Rio Grande do Norte, Santa Catarina and Tocantins). Although in most parts of the states of Bahia, São Paulo, Rio de Janeiro and Rio Grande do Sul 127 V is used, the cities of Santos, Jequié, Jundiaí, São Bernardo do Campo, Novo Friburgo, Bagé, Caxias do Sul and Pelotas run on 220 V. The states of Pernambuco and Piauí use 220 V, except for the cities of Paulista and Teresina (127 V).
 
Good link

"~The reason for this is that in the US 240 V is two-phase, whereas in Europe it is single phase. "

Except 220 volt circuits in the USA are either single phase or three-phase. There is no such animal (as far as I know) as "two-phase".

220 volt residential US circuits have a single phase, with two hot wires that are 180 degrees opposed to each other. They are, however, not considered to be two phases but rather single phase. In a three phase circuit each phase is 120 degrees out from the other. Perhaps it's semantic, but I've never seen any equipment here labeled as "two phase".
 
"split Phase" refers to a type of induction motor used on single phase circuits.It involves use of starting windings,centrifical switches and maybe a capacitor for starting.Once the motor has started-the start winding and capacitor(if used) are switched out of the circuit."Permenant Split phase" refers to motors where the start winding and cap ARE NOT switched out of circuit when the motor is running-these are for low start torque loads such as fans and some blowers.The capacitors in Perm split phase motors are oil filled instead of electrolytic in split phase motor-used for higher start torque loads.The cap and start winding provide a phase shift between the windings so the motor can start-once started it will contunue to run unless stalled below 75% of operating speed.Then the centrifcal switch will close and put the start winding and cap back in the circuit to try to bring the motor back up to speed-if too long the start winding and cap will overheat -or the fuse or circuit breaker to the motor will trip or blow.
 
two interesting links, Steve

And, in my opinion, definitely relevant to our forum's interests.
There were enormous "fireworks", indeed, not that long ago on this topic.
Most folks in the US refer to their 240V connections as "two-phase" and so do I, 'cause I don't ask my mum to pass me the dihydrogenoxide when I want a bottle of water.
The NEC, however, speaks of "split-phase" here.
It also speaks of "two phase wires and one neutral" in older hand books which may have given rise to the whole "two-phase" thingy.
Suggestion: let's not do the fireworks this time and just concentrate on the forum-releveant aspects.
Fer instance: I wonder if US washers would have used more built-in heating if they had not been limited to 120V 15A circuits?
 
Two Phase is an obsolete term used to describe a quite different form of power transmission.]

Two Phase is now obsolete. It was used in the 1800's. It involved having a secondary phase at 90 degrees to the main phase. The secondary phase was used to provide starting torque to motors.

US 220 volt residential service is in fact two-wire single phase, albeit "split" into two legs 180 degrees apart. As far as motors are concerned, split phase provides no starting advantage over non-split single wire single phase. It does provide an advantage in requiring lighter gauge wiring for an equivalent amount of power.
 
Childres, play nice or Auntie Toggles will pull out her swit

There were enormous "fireworks", indeed, not that long ago on this topic.

If there indeed were, I apologize for starting this thread again. Listen, Everyone believes the system to which they adhere is best (it is after all more familar.) This is the nature of the human ego. Once it is understood that we all covet that which is familar, we can then say to ourselves as true diplomats, "well the other person is going to say the same thing about the benefits of their their way as I feel about my way(s)/systems." So way ruffle feathers?

Let's be adults about this and not judge each other's ways. It's is just fascinating to me to note them.

Factoid: The author at one point says 50hz was AEG's idea because it is more "metric" (something about 1,2,5).

One person posted that 110/120v is not "modern" (or was that a private e-mail?) Without having an emotional response to what works well for us here..It is interesting to note that the author says the US wanted to dump it in favor of 220v. Didn't happen. That I did not know.

So here I go again preaching:
DIMPLMACY=> DIPLO-MATIA Literally "double eyes" as in two sets of eyes. One who can see it "my" way and "your" way. It's really not that hard to do.

as grandpa used to say "the DESIRE to DO something is half the battle."

Leaves pupit. Bows.
 
~My Miele W1070 washer's elecrical plate clearly states 220v/50hz 2 phase power.

Methinks the Eupropeans who have 220v between one hot and their neutral think of our continet's two-hot 220v as two-phases.

If one hot is one phase and three hots is three phases what would two hots be?. Le voila. Pas mauvais. Ne'est-ce pas?
 
Here's a good discussion of the obsolete two phase electrical power distribution.

Please note also that I erred in calling modern Amerian 220 volt residential service as "two wire single phase". Apparently the proper designation is either "220 split phase" or "three wire single phase 220".

Just why 220 volt split phase isn't considered two phase probably has a lot to do with how the power is generated by a rotating device, and how the power is used by a motor. And then we are at the limit of my current understanding ;-)

http://en.wikipedia.org/wiki/Two_phase
 
~And then we are at the limit of my current understanding ;-)
LOL oh oh oh two meanings here! Love it!

THANK YOU RICH. Now we now definitively

Next I need to figure out:
1) 277/480v and why does it exist.
2) How center-tapping of transformers creates a neutral
3) What exactly is "impedance"

anyhoo, this world standards thing and how certain customs and traditions evolved is fascinating!
 
Rich, don't you think that George Westinghouse had a lot to do with how we have alternating current and the way electricity is arranged today? I don't think he got along with Thomas Edison over that.
 
Which one of you is an electrician? A commercial industrial UNION electrician? Thats the one to ask. My husband is sleeping or id ask him. He's LU 665 IBEW, so was my Dad. He works with 480 (monsterous transformers required),277 (industrial lighting and such) and 110 every single day.

220's wire requirements is most assuredly not econmical at present. fyi

The thing is, the higher the volts the lower the watts, the lower the bill.
 
Along with 208-120V 480/277 is the next most common 3 phase LV feeder.480/277 is used for larger commercial and industrial power feeds-MANY devices run off 480V 3 ph.Mostly motors.Lighting equipment such as commercial flourescent lights and HID lights run off 277V.Even ran into a condensor fan motor in an AC unit that ran off 277V.Also many larger broadcast transmitters-UHF and VHF TV transmitters run from 480V 3 ph.also 50Kw AM transmitters.Newspaper printing presses run off it too.I even lived in an apartment building that was fed with 480V 3 ph.The building chillers and boiler blower motors ran from the 480V.A transformer bank in the basement of the building stepped the 480V 3ph to 208-120V to run the household loads in the apartments.Other apartment houses I lived in were fed with 208/120V 3 ph.
Impedance is the term used to denote the resistence to current flow in an AC circuit-like resistence is the term used to opposition to current flow in a DC circuit.Impedance is commonly used with power and dist transformers-to show the opposition to current flow in their primary and secondary windings-all of them have this.An impedance factor is marked on the transformer nameplate-if used in a single phase circuit-not important.If the transformer is part of a 3 ph bank-then you want ot try to match the transformers-all of them having the same impedance factor.Generally they try to keep impedance factors as low as possible to maintain system efficency.Otherwise power is lost as heat or magnetic feilds.
Also Nikla Tesla can be credited with the modern AC power systems in use-He was the fellow that came up with the induction motor!Mr Tesla came up with the 3Ph power dist systems.Too bad Westinghouse-the company didn't give Mr. Tesla the credit he deserved-he died a poor man-Sad.The guy was a genius.
The center tap of a transformer winding is considered its electrical "zero" point.And this is usually grounded.The winding is literally tapped at its electrical center-equal number of winding turns on each side.In dist transformers-if they are connected as a three phase bank-the center tap is not used or connected.You are only interested in using the whole winding.
 
Wannapink,

Better go wake hubby... lol...

The wattage (or power) consumed by an appliance is pretty much constant regardless of the voltage. That is, for the same amount of heat, a 110 volt space heater would consume exactly the same amount of power as a 220 volt heater. The 220 volt heater would require thinner gauge wiring because the amperage (current) would be half that on each 220 volt hot leg, than on the single 110 volt hot leg.

I've no doubt that installing 220 volt split phase circuits is more costly than installing 110 volt circuits, because one has to pull two hot wires instead of just one. However, one can get twice as much power out of a 220 volt circuit because the two hot legs can carry the same amount of maximum current as the single 110 volt hot leg. Bingo presto two times one equals twice as much maximum capacity.

Toggle,

Wikipedia has a good entry on three phase power. I'm afraid I've never trained my brain to slow down and figure out exactly what people are talking about with center tap neutrals and Wye and Delta and all that stuff. I'd have to kick out other useless information to cram that in, I fear.

Regarding impedance, what Tolivac said. The impedance of a resistor is the same as its resistance. The impedance of other compenents such as capacitors and inductors is represented by complex numbers that include a real and an imaginary value. In real life, impedance rears its ugly little head when it is mismatched between conductors in a high frequency electromagnetic signal. Such as network data cabling, cable tv cabling, etc. Mismatched impedance can cause reflections etc that degrade the signal so information (but not energy) is lost. If you've ever adapted an old TV to accept coax cable input, you add a device call a balun that matches the 300 ohm impedance of the old TV antenna input to the 75 ohm impedance of the cable. In fact I put baluns on the two TV antennas on my home, so I could use coax cable (shielded, gives better less ghosty signal) to all the sets in the home.
 
Regarding the efficiency

It doesn't seem the 50Hz vs 60Hz argument adds up in terms of efficiency. Here's the stats :

3-21-2007-09-44-1--mrx.jpg
 
The truely major efficiency factors:
1) Modernisation of networks Look how poorly South America, FSU (Former Soviet Union) and Africa perform compared to EU and North America.
2) Concentration of population i.e. if it's all in urban centres you avoid long medium voltage lines.

Re: population density:
Technologically Europe, North America etc would be rather similar.
But:
Somewhere like Finland is huge, but also highly urbanised i.e. populations are concentrated in town/city/village clumps. You can also be damn sure they invest heavily in transmission systems.
Netherlands is one of the most densily populated places on the planet, yet always feels fairly spacious.
Likewise for Belgium.

The likes of Ireland, Newzeland etc are small but low density i.e. lots of one off houses and semi-rural dwelling.
 
Network losses in Latin America & Brazil may be not only infrastructure losses, but the poor frequently "tap-in" to the grid to suck free electricity out. Due to the number and percentage of poor, officals may be forced to turn a blind-eye for the sake of social stability.
 
There are such things as big loads on single phase, though. All of Amtrak's NEC south of NYC is single phase 25hz, and NJT's 60hz segments are single phase. The Red Bank Substation (Coast-2) pulls in from one phase of the 230,000 volt line, and goes to two single phase 10MVA transformers. BTW, the available fault current on the 230kv side exceeds 15,000 amps (!). And there's a big friendly high speed grounding switch on the system. And yeah, they've fired it a few times...

4160 is common for larger water pumps in treatment plants - 2000HP motors, and yes, VFDs provided. Neat stuff
 
Suds, thats who told me that. Dont need to wake him.

Yep, five years of college he had and not at the ABC academy, m'k? I said UNION, card carrying JIW.
 
"The thing is, the higher the volts the lower the watts, the lower the bill."

That is just plain flat-out WRONG, and nayone who makes such a statement doesn't know basic electronics.

Simple as that, and I don't need a union card to know that.
 
the place where I work all of the high power shortwave transmitters run off 4160V 3 ph.Quite a jump from commercial broadcast ones that run off 208 or 480V 3 ph.I am afraid the "higherthe volts-lower the watts-the lower the bill" just doesn't apply to the site I am working at right now.electric bills here are unbeleivable!We measure power in "Megawatt" hrs here.also the 4160V building feeders are stepped down to 208-120,230V3ph and 480-277V 3Ph.4160V is a coomon power feed for larger Govt buildings.
 
I am shocked, shocked I tell you

Ok, the snarkiness level on this thread is rising. So why am I surprised.
Cripes, dahlinks!
The question is interesting, if you want to get all het up, just go read the last thread on this topic - there's enough venom there to poison an army.
Yeah, watts are not the same as amps or volts alone.
You can think of watts as 'work'. They are the product you get when you multiply amps and voltage. It works like this:
120V x 5amps = 600Watts.
240V x 2.5 amps = 600 watts.
As somebody said, the size of the wire is determined by the current load (which we call 'amps') not the voltage. Since you can lower the current by increasing the voltage, high voltage wires are relatively thinner than low voltage wires.
I keep waiting for somebody to explain Ohm's law...then have someone else jump in and point out that 'law' is not politically correct anymore and, anyway, it only applies to resistance loads not inductive or capcitive...
Oh, and, please, my volts * amps = watts only applies to direct current. I can do the formulas for AC and other non-sinosoidal but they fall into the same category as the dihydrogenoxide...
So back to the applications of all this stuff. I notice that some 24" combo washer/dryers in the US are 240V. Does anyone know if the washer motor is also running 240V or just 120?
 
Panthera,

Actually volts*amps=watts applies to AC circuits as well, as long as they are purely resistive loads (like incandescent lighting). Once inductance and capacitance is introduced, however, the alternating current introduces fun stuff like power factor. This is why some AC types of equipment is rated as "volt-amps", probably because that is a more realistic indication of the wire gauge needed in the line circuit to supply the device. In such cases the amp load on the line wiring is virtually always greater than the wattage consumed would otherwise indicate.

For this reason, also, most power companies charge a surcharge on the watts measured by the meter, to account for power factors of less than unity. For most residential accounts, the power factor is assumed to be a certain value, and rates adjusted accordingly. For some if not most commercial/industrial accounts, the utility will measure the actual cumulative power factor of the facility and surcharge accordingly. This gives commercial customers the incentive to fine-tune their equipment to bring the power factor as close to unity as possible.
 
right you are

Rich, and I thought I had said that. Truly, Ohm's law is more an approximation in resistive AC circuits, but close enough for government work in any case.
I worked through what I wrote several times to make sure I did not write anything which could be interpreted wrongly, so forgive me for being cautious.
For the sake of completeness, take a look at the link below for the formulas to calculate actual and apparent power in AC circuits (scroll down).
I have tried so very hard to stay away from the induction/capacitance, serial vs. parallel aspects and, especially Kirchhof's little ditty where everything adds up to zero...
I still think we should waste less time arguing the fine details (surprised nobody has gotten all het up about which "direction" electrons flow) and focus more on the practical aspects of single-phase, split-phase (if that phrase is good enough for the NEC, it is good enough for me) and poly-phase power.

http://www.ibiblio.org/kuphaldt/electricCircuits/Ref/REF_1.html#xtocid1249819
 
Absolutely, Panthera.

The practical impact of single vs. split vs. poly is that few if any of us are lucky enough to have polyphase power in our homes, at least in the USA. I say lucky because I'm looking to buy some machining equipment for my shop at home, and all the older, robust stuff worth looking at runs on three-phase power. A rotary phase converter will be needed to power it, but I dislike having to waste energy doing that conversion, plus the added complexity a phase converter can introduce.

Tree phase is wonderful for running motors, since it provides everything the motor needs to both start and run. Single and split phase both require added windings, capacitors, and a entrifugal switch to start the motor turning, as Tolivac already explained quite well.
 
Rich

My understand of the newer three phase generators is that they are considerably more efficient than the older systems which, having no logic, were relatively wasteful.
I had to relearn trig. when I was studying the basics of electrical engineering - I can't teach the vocabulary for the Natural Sciences and Engineering unless I actually have passed the exams in the various courses. Every so often I manage just a glimpse of the beauty of these systems...
 

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