Get 220v from 127v

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m sleem

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Everyone knows that when we have facility with 220v 3ph the single phase is 127v,
The question is how to get 220v 1ph,2p, from 127v 1ph,1p

As everybody knows:

127+127 = 254v 1ph,2p which is not appropriate for many of equipments :?
 

kwired

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Everyone knows that when we have facility with 220v 3ph the single phase is 127v,
The question is how to get 220v 1ph,2p, from 127v 1ph,1p

As everybody knows:

127+127 = 254v 1ph,2p which is not appropriate for many of equipments :?

If you have 220 volts wye system you will have 127 volts to neutral. This may be common in other countries but is not common in the US. 208/120 volt systems are pretty much what people see for wye systems near that voltage range.

If you want to get 120 volts from that system you will either need an autotransformer (buck - boost transformer) or separately derive the 120 volts you are looking for. Or you could put specific resistance in series with a specific load but can not just use a resistor for general purpose for just any load.
 

m sleem

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You do not add the two voltages.

You multiply, 127V X 1.732 = 220V.

Jumper

The previous equation applicable for 3phase only, my question regarding 1ph, 2p socket.

2poles means summation of 1p+1p.
 

m sleem

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If you have 220 volts wye system you will have 127 volts to neutral. This may be common in other countries but is not common in the US. 208/120 volt systems are pretty much what people see for wye systems near that voltage range.

If you want to get 120 volts from that system you will either need an autotransformer (buck - boost transformer) or separately derive the 120 volts you are looking for. Or you could put specific resistance in series with a specific load but can not just use a resistor for general purpose for just any load.[/QUOTE]

I think you mean 220v
 

jumper

Senior Member
Jumper

The previous equation applicable for 3phase only, my question regarding 1ph, 2p socket.

2poles means summation of 1p+1p.

Your 1ph 2p socket power would have to be derived from a three source.

Here is a tutorial on the subject.

http://www.allaboutcircuits.com/vol_2/chpt_10/5.html

Your summation would only work with a center tapped transformer, in which case you cannot have 127/220.
 

m sleem

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Now i'm making a rennovation of housing buildings, the existing voltage level is 127v 1ph, i'm planing to replace each duplex outlet 127v by single 120v+single 220v.

The dry-type transformer is 480/220v, so if we replace that transformer by 480/208/120, so we can derive 240v by collecting 120+120, would that work?
& what is the effect of 240v for the equipments?
 

jumper

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Now i'm making a rennovation of housing buildings, the existing voltage level is 127v 1ph, i'm planing to replace each duplex outlet 127v by single 120v+single 220v.

The dry-type transformer is 480/220v, so if we replace that transformer by 480/208/120, so we can derive 240v by collecting 120+120, would that work?
& what is the effect of 240v for the equipments?

Oh Mister Dungar, this one is for you.
 

Hv&Lv

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Jumper

The previous equation applicable for 3phase only, my question regarding 1ph, 2p socket.

2poles means summation of 1p+1p.

Only in 180 degree difference.
In three phase applications, which you have, you cannot add the voltages and come up with what you stated. To add the voltages means there is 180 degrees of separation. In a three phase application, the voltages are 120 degrees apart, and you need to multiply as jumper suggested.
 

Hv&Lv

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Now i'm making a rennovation of housing buildings, the existing voltage level is 127v 1ph, i'm planing to replace each duplex outlet 127v by single 120v+single 220v.

The dry-type transformer is 480/220v, so if we replace that transformer by 480/208/120, so we can derive 240v by collecting 120+120, would that work?
& what is the effect of 240v for the equipments?

You would end up with 208 volts at the socket, not 220 volts.

According to your numbers, you seem to have a 208/120 three phase system now. The primary voltage is just a little high.
 
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Hv&Lv

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Maybe, but Google shows 220/127V systems exist around the world.


I just looked at where the OP was from...

but from what I can gather, they are built just like our wye banks.
 
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m sleem

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Finally i caught it :D for the Y connection the 3ph voltage level is equal to the line voltage (phase to phase)

And so we can apply Jumper equation:

the line voltage = 1.73 x phase voltage


By the center tapped transformer which we can get 180 degree difference so the line voltage will be (phase + phase)



Thanx for all.
 

jim dungar

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Now i'm making a rennovation of housing buildings, the existing voltage level is 127v 1ph, i'm planing to replace each duplex outlet 127v by single 120v+single 220v.

The dry-type transformer is 480/220v, so if we replace that transformer by 480/208/120, so we can derive 240v by collecting 120+120, would that work?
& what is the effect of 240v for the equipments?

If you are outside of North America, you will have electical distribution systems that are fundamentally different, and somewhat restricted, from those you will see in the discussions on this forum.

You need to have some understanding of electrical theory using vectorial math. You also need to be careful with your terms, there is a big difference between a 'phase conductor' and a 'phase voltage', so I try to use stick with terms like Line or Hot and Neutral when discussing conductors.

Most non-North American residential systems are 2-wire circuits derived from 3-phase 4-wire transformer connections. This is not true in the US where the majority of systems are 3-wire circuits derived from 3-wire transformer connections.

We also have different voltage levels which can really add confusion.
Our National Electric Code requires use to use the nominal voltages of 120V, 208V, 240V, 480V when describing electrical systems, however most of our utilization equipment has nameplates voltages which are less than system voltages, such as motors labeled as 230V. One result of this, is our tendency to round voltages up or down to the nominal US system voltages even when we are discussing non-North American systems. We also do not have a single method of 'writing down' our voltages, many try to follow ANSI recommendations, however many, if not most, of our utilities and electricians do not.

So:

In the US, we have common non-industrial voltages of:
120V 1-phase 2-wire
120/240V 1-phase 3-wire (the 120V comes from center-tapping the 240V)
120/208V 1-phase 3-wire (the 120V comes from the midpoint of a 208V wye, or star, connection)
240V 1-phase 2-wire

208Y/120V 3-phase 4-wire
240/120V 3-phase 4-wire (the 120V comes from center-tapping one 240V winding of a delta connection)
480Y/277V 3-phase 4-wire

In other parts of the world, it seems they only have:
127V 1-phase 2-wire (derived from the midpoint of a 220V star connection)
230V 1-phase 2-wire (although some areas, until recently, were 220V while others were 240V)
400Y/230 3-phase 4-wire.

What I am getting at is: be confident that we are discussing the same system. Simply using voltages levels as descriptors can definitely lead to the improper conclusions.
 

m sleem

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................................

So:

In the US, we have common non-industrial voltages of:
120V 1-phase 2-wire
120/240V 1-phase 3-wire (the 120V comes from center-tapping the 240V)
120/208V 1-phase 3-wire (the 120V comes from the midpoint of a 208V wye, or star, connection)
240V 1-phase 2-wire

208Y/120V 3-phase 4-wire
240/120V 3-phase 4-wire (the 120V comes from center-tapping one 240V winding of a delta connection)
480Y/277V 3-phase 4-wire

In other parts of the world, it seems they only have:
127V 1-phase 2-wire (derived from the midpoint of a 220V star connection)
230V 1-phase 2-wire (although some areas, until recently, were 220V while others were 240V)
400Y/230 3-phase 4-wire.

What I am getting at is: be confident that we are discussing the same system. Simply using voltages levels as descriptors can definitely lead to the improper conclusions.

Thats very helpful :thumbsup:
 
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kwired

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If you have 220 volts wye system you will have 127 volts to neutral. This may be common in other countries but is not common in the US. 208/120 volt systems are pretty much what people see for wye systems near that voltage range.

If you want to get 120 volts from that system you will either need an autotransformer (buck - boost transformer) or separately derive the 120 volts you are looking for. Or you could put specific resistance in series with a specific load but can not just use a resistor for general purpose for just any load.[/QUOTE]

I think you mean 220v
You indicated you already have 220 volts, and if it is 127 to neutral then I have to assume it is a three phase wye system because that does work for the 1.73 multiplier for a wye system. A single phase system or a delta system would not be possible to have both of those voltages on same system.

Since you say you have 220 and 127 what voltage are you desiring to have? 120/240? 208/120? If you are served by a 480 volt system, sounds like you would be better off getting a 480 x 120/240 or 480 x 120/208 instead of trying to transform from 220/127, or you may actually have a 120/208 and need to change the input taps, what is actual reading of primary voltage?
 
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