# Help 480V High Leg Delta 3P .??



## nebio (Mar 21, 2018)

Here is the specs I have been given for a machine from the EU coming to the USA. 

If you use a high-leg delta connection (see the previous picture), you have 3 phase and 1 neutral and 1 ground. If you measure the voltage between phase and phase you get 480V. It is good, but if you measure the voltage between 1 phase and neutral you need to measure 240V. If you measure more you need to reduce the inlet 480V to 400V. Originally our machine works well on 400V, but each phase is no more, than 240V.

In the diagram (which I can not upload) they show a delta with ABC and then a separate G and N which are drawn connecting to the delta. This is not Wye

We have 480v 3 Phase from the main but this is 3 wire and then units are grounded. 

Can this service be a High Leg Delta or do I need a transformer and then 5 wires?


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## RePhase277 (Feb 5, 2008)

I have seen 480 V delta high legs, but they were old and rare.

This machine sounds like it was designed to run on a 400Y/230 V system. You probably need a transformer. I use Bruce Electric in NY for those specialty transformers.


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## JRaef (Mar 23, 2009)

There is no such thing as 480V "high leg" delta; there is 480V delta or 480/277V wye. People outside of the US don't understand our distribution systems very well and make all kinds of ignorant statements.

Just because you have only 3 phases coming out of a distribution panel or MCC, doesn't necessarily mean you have 480V delta, it could be that the neutral was just not brought out because nobody was using it and they didn't want to waste money on the conductor for no reason, Whether you have a delta or wye service is relevant at the SERVICE ENTRANCE.

If their product is designed for 400V 50Hz in Europe or elsewhere outside of North America, then it is designed for a Wye system (they call it Star, same thing) where the L-N voltage is 230V. If their system MUST have no more than 230V L-N, then it is not suitable for use here in the US.


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## frenchelectrican (Mar 15, 2007)

According to your profile it say " Engineer " .,

You should concant the equiment manufacter to see what they do with that machine to reconferaton to North Americian standard.

You can get this in Delta or Wye on 480 volts.

I dealt alot of both 400 and 480 volts equiments so I am pretty famuiar with it. 

If your machinery do set up to work with 60 HZ source then it is not a issue but the only nice gotcha if you have VSD's then you need to pay attetion to them due the EU specs are set for wye ( star ) system so check the VSD installment and operation manual for details to work on 480 volts delta system. 

If any reason why your equiment do need neutral then two way you can do this is run in wye supply otherwise Delta Y transfomer ( 480- 400/240 ) will do it. 

Ya there is high leg delta but super rare and not being used anymore.


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## varmit (Apr 19, 2009)

If this machine requires a neutral, probably some of the controls or small loads were configured for 220 VAC 50 Hz. I have seen some European machines where for whatever reason, the neutral was connected to one end of the motor windings. The motors will work fine without this strange connection.

It sounds as if you will need to do some research with the machine vendor to determine, for certain, the power requirements. Also, verify the building electrical characteristics. A 480 volt high leg service is a very rare thing. Usually you have either (a) 480/277 with or without a neutral, (b) 480 corner grounded, 480 ungrounded or (d) 480 volt resistor grounded.

Usually, BUT NOT ALWAYS, a 50 Hz machine can operate on 60 Hz. Pumps and fans can be a problem due to their higher current draw at the higher 60 Hz speed.

Good luck.


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## nebio (Mar 21, 2018)

RePhase277 said:


> I have seen 480 V delta high legs, but they were old and rare.
> 
> This machine sounds like it was designed to run on a 400Y/230 V system. You probably need a transformer. I use Bruce Electric in NY for those specialty transformers.


Yes you are right... after looking at the diagram it seems to be 240V 3 Phase with a stinger leg of 400V ... with both neutral and ground. Does this make sense? Kinda like the USA with the 208v and 240v stinger? 

This machine is from eastern Europe. So they have said 3 phase 240V high leg (stinger 400V)

Would 1 transformer cover this? My feed is standard 480v Delta 3P


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## nebio (Mar 21, 2018)

JRaef said:


> There is no such thing as 480V "high leg" delta; there is 480V delta or 480/277V wye. People outside of the US don't understand our distribution systems very well and make all kinds of ignorant statements.
> 
> Just because you have only 3 phases coming out of a distribution panel or MCC, doesn't necessarily mean you have 480V delta, it could be that the neutral was just not brought out because nobody was using it and they didn't want to waste money on the conductor for no reason, Whether you have a delta or wye service is relevant at the SERVICE ENTRANCE.
> 
> If their product is designed for 400V 50Hz in Europe or elsewhere outside of North America, then it is designed for a Wye system (they call it Star, same thing) where the L-N voltage is 230V. If their system MUST have no more than 230V L-N, then it is not suitable for use here in the US.


]]


After more communication. The equipment is from Eastern Europe. Our service is 480v Delta 3P

They are saying that this is 240V 3ph with a stinger leg of 400v (similar to some power I have seen here in the states with a high leg.) Yes.. this shows 5 wire total. 3 hots (2 normal, 1 high leg) 1 neutral and 1 ground. Can this be accomplished with a specialty transformer from my native 480v 3ph Delta? Any suggestions? Just a lowly Aeronautical Engineer trying to convey this between parties.


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## nebio (Mar 21, 2018)

frenchelectrican said:


> According to your profile it say " Engineer " .,
> 
> You should concant the equiment manufacter to see what they do with that machine to reconferaton to North Americian standard.
> 
> ...


Thank you for your time. Yes aeronautical engineer who knows when he is out of his league. They do spec out a neutral. And yes I will check the VFD to see if they are good with 60hz (since their native is 50hz). Thing is I need to have the service in place before they come to install. So.. the Equipment is coming from Hungary .. I believe their service is 240V with a stinger leg @ 400V. So... can this be accomplished with one transformer when I am starting with 480V 3p Delta.? 

They said 240V from A and C and 400V from B (high leg) to Neutral is 400v


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## nebio (Mar 21, 2018)

varmit said:


> If this machine requires a neutral, probably some of the controls or small loads were configured for 220 VAC 50 Hz. I have seen some European machines where for whatever reason, the neutral was connected to one end of the motor windings. The motors will work fine without this strange connection.
> 
> It sounds as if you will need to do some research with the machine vendor to determine, for certain, the power requirements. Also, verify the building electrical characteristics. A 480 volt high leg service is a very rare thing. Usually you have either (a) 480/277 with or without a neutral, (b) 480 corner grounded, 480 ungrounded or (d) 480 volt resistor grounded.
> 
> ...


Building Service American 60hs 480v 3P Delta

Equipment is from Eastern Europe 5 wire (2 @ 240V, high leg at 400V to N) and then Neutral and Ground Wire. 

Question is how to replicate from my 480V 3P delta service. Any suggestions on a manufacturer who makes these? 

There are electronic VFD's here that I am pretty sure are 50hz/60hz can you expand on the fact that if the pump is wound for 50hz we may have an issue even though we are running through a VFD?


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## RePhase277 (Feb 5, 2008)

I seriously doubt this machine NEEDS a 240 V delta with a 400 V high leg. I suspect that the supplier just THINKS this is how American electrical systems are. 

I would definitely get on the phone with the person who knew the best English and get to the bottom of it. My bet is that it is designed to work on a 400Y/230 volt system that is standard across Europe. You will be hard-pressed to find a transformer to turn 480 volts into a delta with a 400 V high leg, but a 400 V wye is easy. I've bought 5 or 6 in the last 10 years.


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## RePhase277 (Feb 5, 2008)

I think you have enough posts now to put up a picture of the diagram you have so we can take a look at it.


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## RePhase277 (Feb 5, 2008)

nebio said:


> Thank you for your time. Yes aeronautical engineer who knows when he is out of his league. They do spec out a neutral. And yes I will check the VFD to see if they are good with 60hz (since their native is 50hz). Thing is I need to have the service in place before they come to install. So.. the Equipment is coming from Hungary .. I believe their service is 240V with a stinger leg @ 400V. So... can this be accomplished with one transformer when I am starting with 480V 3p Delta.?
> 
> They said 240V from A and C and 400V from B (high leg) to Neutral is 400v


I don't think you will find a transformer to do that off-the-shelf, of it is truly a requirement. You'll either need to have one manufactured($$$$) or you could use three single phase 480-240 V transformers make the delta connection externally. This is the route I would go if I absolutely, positively, for-sure NEEDED 240 V with a 400 V high leg.


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## NewElect85 (Dec 24, 2017)

We wired a project about a year ago with just about the same problem.
They brought in European braiding machines for an aviation application.
They had some compliance issues and just decided to bring in a electric generator that would give them the 50hz and the voltage they needed.
The generator was powered by a 480 volt electric motor. The output was fed into a separate panelboard and distributed to the machines. 

It seemed a bit Rube Goldberg for me but, it's their money.


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## nebio (Mar 21, 2018)

RePhase277 said:


> I think you have enough posts now to put up a picture of the diagram you have so we can take a look at it.


Thank you Rephase I have to post 20 before I can insert a pic. Or link to a URL 

i64.tinypic.com/2lvbrjk.jpg


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## nebio (Mar 21, 2018)

No that did not work.. anyway.. I will try my best to figure out how to post the diagram or upload it to another location. 

This link works. ibb.co/cP2RSx


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## nebio (Mar 21, 2018)

RePhase277 said:


> I don't think you will find a transformer to do that off-the-shelf, of it is truly a requirement. You'll either need to have one manufactured($$$$) or you could use three single phase 480-240 V transformers make the delta connection externally. This is the route I would go if I absolutely, positively, for-sure NEEDED 240 V with a 400 V high leg.


This came from the Manufacturer based on the image link I sent 

*The best if you have High-led delta transformer: in this time we have 480V in between ABC points, but we have only 240V between AN and AC points.*


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## frenchelectrican (Mar 15, 2007)

nebio said:


> Thank you for your time. Yes aeronautical engineer who knows when he is out of his league. They do spec out a neutral. And yes I will check the VFD to see if they are good with 60hz (since their native is 50hz). Thing is I need to have the service in place before they come to install. So.. the Equipment is coming from Hungary .. I believe their service is 240V with a stinger leg @ 400V. So... can this be accomplished with one transformer when I am starting with 480V 3p Delta.?
> 
> They said 240V from A and C and 400V from B (high leg) to Neutral is 400v


My simple soluation is just set up that machine for straight 240 or 400 volts 3 phase supply and if anything need netural just set up a small transformer for this useage. 

And just get a Delta wye transfomer which it can take 480 volts input and the output will be 400/240 volts. direct and simple. ( I would not mess around with high leg delta anyway ) 


But make sure the motors and related system can handle 60 Hz due you should know 60 HZ the motor(s) will run faster than 50 HZ source will be.


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## nebio (Mar 21, 2018)

Continued from Manufacturer

*If you use a high-leg delta connection (see the previous picture), you have 3 phase and 1 neutral and 1 ground. If you measure the voltage between phase and phase you get 480V. It is good, but if you measure the voltage between 1 phase and neutral you need to measure 240V. If you measure more you need to reduce the inlet 480V to 400V. Originally the iCPC works well on 400V, but each phase is no more, than 240V.*


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## nebio (Mar 21, 2018)

frenchelectrican said:


> My simple soluation is just set up that machine for straight 240 or 400 volts 3 phase supply and if anything need netural just set up a small transformer for this useage.
> 
> And just get a Delta wye transfomer which it can take 480 volts input and the output will be 400/240 volts. direct and simple. ( I would not mess around with high leg delta anyway )
> 
> ...


I see... I will be talking with them today and see what I find out as they have had 1 other install in the USA before. That's not to say they are not screwing something up. I am sure that the motors are 50hz and yes I am aware of the difference. I will have to adjust for the cycle time, other than that the hz should not be an issue right?


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## RePhase277 (Feb 5, 2008)

nebio said:


> This came from the Manufacturer based on the image link I sent
> 
> *The best if you have High-led delta transformer: in this time we have 480V in between ABC points, but we have only 240V between AN and AC points.*


That description would be a 480/240 delta with a 415 volt high leg. This is going all over the map. Best thing is to ask them if it actually needs a neutral. Ask them if a wye connected system would be OK. I say this because it's hard to believe that a European machine would REQUIRE a high leg for anything. It's just not a system they have used over there. I honestly think they are confused about what we have in the US.

Try this: Ask them what the machine runs on in Hungary.


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## RePhase277 (Feb 5, 2008)

nebio said:


> I see... I will be talking with them today and see what I find out as they have had 1 other install in the USA before. That's not to say they are not screwing something up. I am sure that the motors are 50hz and yes I am aware of the difference. I will have to adjust for the cycle time, other than that the hz should not be an issue right?


Not through a VFD, no.


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## nebio (Mar 21, 2018)

*Solved*

Thank everyone for their input. Finally got some kind of an answer. Was able to talk to someone else who had the install of the same equipment. The manufacturer got all confused because we have 480v 3 phase service as opposed to a lower input voltage. Although they maintained that this was a high leg delta transformer the one the customer in the USA is using is 

480V 3P input >> 400VY/231 Out

Thanks for all the help. Just hoping that this actually works with the voltages and phases they said the machine was going to use originally.


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## Wiresmith (Feb 9, 2013)

JRaef said:


> There is no such thing as 480V "high leg" delta; there is 480V delta or 480/277V wye. People outside of the US don't understand our distribution systems very well and make all kinds of ignorant statements.


we have 2 old plants with it around here
480 motors, 240 lighting


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## Helmut (May 7, 2014)

Be interested in knowing what this machine does?

Swapping one motor, might be cheaper than the transformer route.


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## JRaef (Mar 23, 2009)

nebio said:


> after looking at the diagram it seems to be 240V 3 Phase with a stinger leg of 400V ... So they have said 3 phase 240V high leg (stinger 400V)


By the way, none of this works mathematically...

The "stinger" leg voltage on a Delta transformer arrangement with a center tapped winding is ALWAYS the relationship of the Ph-Ph voltage to 1/2 of the sq. rt. of 3.

If they had a 240V 3 phase Delta system with one winding center tapped, the P-N on two legs would be 120V, the "stinger leg" would be 208V. (240 x .5 x 1.732)

If they had a 400V 3 phase Delta with a center tap on one winding, it would be 200V Ph-N on two legs, then 346V Ph-N on the stinger leg. (400 x .5 x 1.732)

To get a "400V stinger leg", the Ph-Ph voltage would have to be 462V, and nobody in that part of the world would use 462V.


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## RePhase277 (Feb 5, 2008)

JRaef said:


> By the way, none of this works mathematically...
> 
> The "stinger" leg voltage on a Delta transformer arrangement with a center tapped winding is ALWAYS the relationship of the Ph-Ph voltage to 1/2 of the sq. rt. of 3.
> 
> ...


A 480 V delta with a center tapped phase would have a 416 V high leg, which was mention at some point in all the mess. I've seen maybe 3. They were oooooollllllddddd.Turns out, as was predicted, the Europeans had no idea what we had over here.


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## Bird dog (Oct 27, 2015)

RePhase277 said:


> A 480 V delta with a center tapped phase would have a 416 V high leg, which was mention at some point in all the mess. I've seen maybe 3. They were oooooollllllddddd.Turns out, as was predicted, the Europeans had no idea what we had over here.


Interestingly, there are also larger military gensets with 416/240v Y, 50hz.


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