transformer voltage

[StanleySmith]

I'm using a 460VAC/230VAC single phase transformer. My customer insists wanting to have 440VAC/220VAC one instead. The ratio between the two transformers are the same. How different are the two? Are they essentially the same ?

Thank you,

 

[davidbeach]

They are both 2:1 transformers insulated for approximately the same voltage level. Going down in voltage is never (OK, nearly never in reasonable cases) going to be a problem. Going up in voltage can be a problem as there is a maximum V/Hz value for all iron cored machines (transformer is an electrical machine even with no moving parts). So using a 460:230V transformer at 440:220V will not be a problem; using a 440:220V transformer at 460:230V might be a problem. More likely that 440:220V transformer would become a problem somewhere in the 480-500V range on the high side.

 

[victa1288]

The voltage the sec. side of transformer should be 230V, The voltage level on load side should be 220V. You can always use a tap changer to adjust the voltage level of sec. side.

 

[waross]

Hi StanleySmith
What part of the world are you in. Those voltages have been obsolete in North America for quite a while now. North American standard voltages are 120 V, 208 V, 240 V, 277 V, 347 V, 480 V and 600 V.
yours

 

[eehusker]

The difference is described in the ANSI standard for Voltage. I don't have it in front of me so I can't tell you the standard number.

But in a nutshell, they have two voltage levels. Service Voltage and Utilization Voltage. This recognizes the fact that you will have some voltage drop in your distribution and branch circuit systems.

You will notice that your house has a nominal 120/240 Volt system, but that most appliances (toasters, microwaves, hair dryers, etc.) are listed for either 110 or 115 Volts.

At industrial levels, you buy a 460 Volt motor for connection to a 480 Volt system.

 

[waross]

I understand that the EU voltage is 230 volts. I understand that an old UK voltage is 220 volts. The standard now in North America is 240 volts. In the 50s there was appliances made for 110 volts, then 112 volts, then 115 volts, then 117 volts. The progression was at a rate of 0.5 volts a year. The progression stopped at 120 volts and it has been 120 volts ever since. Any appliances rated at 220 volts in North America are either imported or very old.
460 volts was chosen as a compromise voltage for motors so as to be compatable with the old 440 volt delta iondustrial systems in wide use and the newer 480 volt wye industrial systems.
I changed out some 333KVA / 460 V transformers a few years ago. They had been used for years on 480 volts and were replaced with 480 volt units.
StanleySmith
I would guess that you are in the UK and your customer is remembering the older common voltage. What is you applied voltage?

 

[ScottyUK]

Almost right! The UK was originally 240V[±]6%. Europe was 220V[±]whatever%. The Eurocracy in its boundless desire to interfere has decided that 230V will be the new nominal voltage standard, but have basically just widened the tolerance bands so the old 240V+6% is the upper limit and 220V-?% is the lower limit. Very little has changed in terms of distribution infrastructure, although that will follow as assests wear out. Distribution plant has such a long life that I expect that 240V supplies will outlast me. Equipment now has to operate to an acceptable standard over a wider range of possible supply voltages - not so bad with switchmode stuff, but not so good for anything with a ferrous core.

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I don't suffer from insanity. I enjoy it...

 

[waross]

Thanks ScottyUK.
respectfully

 

[stevenal]

The standard eehusker is referring to is ANSI C84.1. 115, 200, 230, 460, and 575 are the nominal utilization voltages on motor nameplates and controls. 120, 208, 240, 480, and 600 are the corresponding system voltages. Most appliance nameplates show the system voltage rather than the utilization. A 120 volt appliance should be able to function from 106 to 127.

 

[waross]

Thanks stevenal
That was my understanding.
respectfully