Why Is American 220v Not Considered 2 Phase?

Yes John H. however- the cap is in series with which winding? The start winding. Same thing in the 220 volt configuration except the run windings are in series not parallel, and the start leg is in parallel with one of the run legs. The junction of the two run windings should be 0, by voltage divider. And that's the reason you can use the same 110 volt start winding for 220. You're still getting a phase shift between the start leg and the parallel run leg. Right?
Mark S.
 
OK just for a little more mud in the water, below are the secondaries of both delta and wye transformers.
when ,in the US, you use 220 or 110 you are using two connection points, NOT two different phases as you can visualize from the pix.
Other parts of the world use delta with it's "floating" /no ground. Have run into both types working on cruise ship equipment. A meter reading from one leg of a delta sys to "ground" produces some ...interesting... results.

delstar-600x207.jpg
 
Earlier, it was mentioned, incorrectly imo, that the EU and global power uses only one line for power.
Most of the world is 220V (240V) single phase, residential, at 50 Hz.

The std residential single phase service uses 2 lines for power.
And a green/yellow safety ground, not used at all.

Unlike in the US, plugs are not keyed.
You can use either line, since its AC, and both lines carry an identical load.

Typically, up to about 4-6 kW is single phase, and around 4-6 kW you start to get 3-phase used, for example for saunas (or larger jacuzzi).
Most new EU residential installs have 3-phase at the fuse box, as standard.
And typical power levels are 10-15 kW, up to 20 kW, new, in the EU.

I have about a 20 kW install, older, in Spain, and this is quite unusual.
Technically, the service is iirc about 14-16 kW, 380 V 3-phase, with all appliances done at 220V single phase.

But I have 380V 3-phase wired in several places, just not in use at the moment.
So I could connect say an electric car plug, and charge at 14-16 kW, if I wanted to.

Any electrician can connect the plug, and it costs about 100$ (legal install, no paperwork necessary).
Since I already have the service, and internal wiring, the current installs like mine are grandfathered in.
 
I think terminologies are the problem here. different countries and possibly even states use different names for the same things, then to add to the confusion they use the same names to describe different things.

Single phase is single phase irrespective of the voltage in single phase the sine wave goes from + volts to - volts of the same value, be it 110 or 220 0r even 240v. crossing the zero line midway, all phases derived from 3 phase will be 120 deg apart, a transformer cannot change this, I have never heard of phases being 90 or 180 deg apart unless it came from a two phase generator or rotary converter, but I have never seen or heard of one, I'm sure it's possible.

A two phase service to a consumer will simply be two of the three phases split from a three phase supply. each phase will consist of a single active wire and a common neutral wire. two phase is not normally used to run motors but is often used to supply electric cookers and other heating equipment. Two or three phase will be supplied to a consumer where a single phase cannot supply sufficient current for the total load.
 
If not so good memory is somewhat correct...There was some 2 phase power systems back in the rust belt area from the early days when ac and dc power systems were both in use.

The phases were 90 degrees apart maybe and still in use a few years back when we read about it.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
Just to add to the confusion.
Also I had heard the Detroit still had some 2 phase power around 20 years ago. They may still have some3-phase_wye_diagram.png deltawye_figure3.gif
 
The American system has always confused me. Here in downunder we have a system similar to Europe. distribution from the power station is via 3 wire 3 ph at a variety of very high voltages, this is broken down into local service areas at substation and sent out as 3ph 4wire ie. 3 actives and a neutral at usually around 3,300v This is then further reduced with local area transformers to 415/440v 3 ph still in 4 wire configuration. This is then supplied on the power poles throughout the local area.

Instead of having the small transformers, or pole pigs, as you guys call them we have much larger transformers servicing a larger area, this is all 4 wire 3ph 415/440v. the individual supply to local consumer can be single ph 2 ph or 3 ph depending on consumption requirements.

Most homes that have gas available (that is domestic natural gas, not petrol) used for cooking , hot water and heating, will only have single ph, those that require more power if they are all electric, cooking hot water and heating etc will often have 2 ph, ( this is not split phase as in US, but two of the three phases at 120 deg. apart, from the pole.

The two phases will be distributed around the house as single ph only, possibly with the exception of the cooker which if large may use the two phases separately to supply different elements. This can result in an interesting situation where one of the two phases fails, half the lights and appliances in the house will still work but the others will not. This can also happen in a 3 ph installation.

Electricity is quite expensive here, on average about double the average price in the US so it is rarely used for heating other that cooking.

This two phase is never used for motors. In cases where large air conditioning or swimming pools or home workshop 3 ph can be supplied direct from the pole.

My house is supplied with 3ph but only has one 3 ph outlet which is in the garage. I was going to get a 3ph welder, but never did. All other appliances use single ph 240v. So it sits there unused. I could fit a 3ph motor to my lathe, but why bother the single ph motor gives me all the power I need. Maybe one day if the motor ever needs replacing.
 
In AU most residences have 3 phase 240v available outside their houses, in US most residences have only single phase available and it appears as 240 volts which is tapped and grounded in the center (split phase), giving 120 volts for small appliances and 240 volt for larger ones. AU uses small numbers of large transformers serving many houses, US uses large numbers of small transformers serving at most 3-4 houses.
 
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