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

[toggleswitch]

Speaking of Japanese eletricty in another thread caused me to stumble upon this.
Quite a good read, IMHO.

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

OOOOH that quote formt he text is gonna cause some discussion!

http://users.pandora.be/worldstandards/electricity.htm#plugs

 

[toggleswitch]

~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).

 

[toggleswitch]

This is cool site!

http://users.pandora.be/worldstandards/index.htm

 

[sudsmaster]

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".

 

[brisnat81]

From what I've read, isnt the term usually used, "Split Phase"

 

[tolivac]

"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.

 

[panthera]

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?

 

[sudsmaster]

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.

 

[launderess]

Oh I Don't Know About That

My Miele W1070 washer's elecrical plate clearly states 220v/50hz 2 phase power. Now the machine is "old" but from the 1990's, not 1800's.

L.

 

[petek]

Do I detect huffiness LOL

 

[toggleswitch]

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.

 

[toggleswitch]

~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?

 

[sudsmaster]

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 ;-)

Two-phase - Wikipedia

en.wikipedia.org

 

[toggleswitch]

~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!

 

[neptunebob]

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.

 

[wannapinkset]

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.

 

[tolivac]

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.

 

[sudsmaster]

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.

 

[MrX]

Regarding the efficiency

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