Electrical conversion

Status
Not open for further replies.
W

wrogan

New member
I am having an European machine installed. The book I have calls for 3 phase 400 volts at 50/60 hz. The Tech for the company says I have to have 480 volts American. My problem is that a while back the 480 tap on my existing xformer burned out so I droped to a lower tap. My 3 phase voltage is at 456 volts. What is the American conversion of 400 volts European. My xformer is 480 delta primary and 240-120 secondary. Can I get some help with this as I am trying to save from having to buy a new xformer. Thanks Walt
 
wrogan said:
I am having an European machine installed. The book I have calls for 3 phase 400 volts at 50/60 hz. The Tech for the company says I have to have 480 volts American.
Click to expand...

He really said that?

wrogan said:
My problem is that a while back the 480 tap on my existing xformer burned out so I droped to a lower tap. My 3 phase voltage is at 456 volts.My xformer is 480 delta primary and 240-120 secondary. Can I get some help with this as I am trying to save from having to buy a new xformer. Thanks Walt
Click to expand...

Not following you at all, you talking about 2 different transformers here?

wrogan said:
What is the American conversion of 400 volts European.
Click to expand...
Um, 400V.
 
wrogan said:
I am having an European machine installed. The book I have calls for 3 phase 400 volts at 50/60 hz. The Tech for the company says I have to have 480 volts American.
Click to expand...
There is no difference between European Volts and American Volts. There is no conversion factor from one to the other
If the machine manufacturer it wants 400V, then give it 400V.
 
wrogan said:
I am having an European machine installed. The book I have calls for 3 phase 400 volts at 50/60 hz. The Tech for the company says I have to have 480 volts American. My problem is that a while back the 480 tap on my existing xformer burned out so I droped to a lower tap. My 3 phase voltage is at 456 volts. What is the American conversion of 400 volts European. My xformer is 480 delta primary and 240-120 secondary. Can I get some help with this as I am trying to save from having to buy a new xformer. Thanks Walt
Click to expand...

It sounds like you have an Auto Transformer if you have multiple taps. If the transformer is working properly, 456V would be good for the machine IMO.
I have several European machines with 400V motors and we use 440V to power them with no problem. As Zog said, there is no conversion. 400V or any voltage is the same here as in Europe. What can be different is some are 50Hz. You need to ask the Tech why he's requiring 480V if the book says 400V. Unless the motor has been changed since the book was written or in some cases, a motor has been rewound for 480V. Better yet, just look at the name plate on the motor.



Sorry Besoeker, we posted at the same time!
 
Last edited:
What type of starter are you using, acrossed the line or VFD

We do alot of industrial work and come across this quite a bit.(mostly in flour mills) On the motor nameplate it might give you multiple voltage rating depending on how it is hooked up.(dual voltage rated motor) Y or D // D or Y one would be low voltage ond the other high 400/460.. Or the motor might be rated to handle the difference in voltage. I tried to attach a pic that shows this but had little success so I will try to type it in.

Actual nameplate Volts and Amps --- 230-277//400-480v -- 3.3//1.9A

This is what we come across don't know if it helps but the motor maneplate is the ticket
 
Besoeker said:
There is no difference between European Volts and American Volts. ...
Click to expand...
I don't know about that. I've heard the French Volts are a bit snootier than ours, and the German Volts are definitely stricter. Then there's the rumor that in Poland, they have CA current instead of AC.

Ba-dum-bump <rim shot>

Thanks folks, I'm here all week... :grin:
 
wrogan said:
I am having an European machine installed. The book I have calls for 3 phase 400 volts at 50/60 hz. The Tech for the company says I have to have 480 volts American. My problem is that a while back the 480 tap on my existing xformer burned out so I droped to a lower tap. My 3 phase voltage is at 456 volts. What is the American conversion of 400 volts European. My xformer is 480 delta primary and 240-120 secondary. Can I get some help with this as I am trying to save from having to buy a new xformer. Thanks Walt
Click to expand...

So many issues...

  • Replace that transformer. If you have "burned out" a tap, you have other serious problems and a severe failure just waiting for the most inopportune time to happen. Murphy rules, you should not tempt him.
  • If your machine has AC motors that are powered directly from the line power, meaning not through VFDs, then I seriously doubt the voltage spec would read 400V 50/60Hz. An AC motor would not work that way. So most likely you have no motors, DC motors fed by drives, or you have servo motors fed by amplifiers that are essentially Switch Mode Power Supplies that convert AC to DC. In any of those 3 scenarios, you MUST supply the 400V. That means getting a suitable transformer that will provide you with 400V.
  • Aside from the power specification, machines from the EU often use a Phase-Neutral connection as a source of 240V power for feeding control systems and power supplies. If you hook up to 480V delta, Delta systems have no Neutral. Nothing will work and if your machine neutral is internally bonded to ground everything will most likely fry.
  • You say your transformer is 480-120/240V delta? Then you have something totally wrong, or you are leaving out some details, such as you have 240V 3 phase in your plant and were planning on back feeding that burned out transformer? Still wrong on multiple levels.
  • You need to fully understand EXACTLY what your machine requires and what you have available. Whatever your company saved by buying that machine from a European supplier needs to be reconciled with the fact that you cannot through good money after bad and try to salvage existing inappropriate equipment that may end up frying your expensive new purchase.
 
Last edited:
wrogan said:
I am having an European machine installed. The book I have calls for 3 phase 400 volts at 50/60 hz.
Click to expand...
Did you get the nameplate rating correct? 400V @ 50Hz is okay!

If the machine is a motor load, then 480V@ 60Hz won't be a problem on that motor. Keep in mind that an increase in supply frequency will increase the inductance of the motor windings: So, using a motor designed for 50Hz could still be usable using 400V X (60Hz/50Hz) = 480V @ 60Hz. The key here is V/f ratio (volts per hertz ratio). At 50 Hz, 400 volts, the V/f ratio is = 400/50 = 8 and the V/f ratio when using the same motor @480V, 60 Hz is = 480/60 = 8. Equal.

What you have to verify is the loading of the motor, careful not to overload it. The motor designed for 50Hz will run faster at 60 Hz and the motor output per design will not be enough to carry the actual load assuming the load torque is fixed and ran at a higher speed of rotation:
Code: 
HP = Torque X Speed /5250

HP[SIZE="1"](60)[/SIZE]        Torque[SIZE="1"]60[/SIZE] X Speed[SIZE="1"]60[/SIZE]
---------  = ------------------------
HP[SIZE="1"](50)[/SIZE]        Torque[SIZE="1"]50[/SIZE] X Speed[SIZE="1"]50[/SIZE]

HP[SIZE="1"](60)[/SIZE]        Speed[SIZE="1"]50[/SIZE] X 60/50
---------  = -----------------
HP[SIZE="1"](50)[/SIZE]        Speed[SIZE="1"]50[/SIZE]

HP[SIZE="1"](60)[/SIZE]      
---------  = 60/60 = 120%
HP[SIZE="1"](50)[/SIZE]

Clearly, the motor will draw 120% of shaft output at 60Hz for the same torque load.

But if there are other accessories of that machine of yours that really need 400V, you need to provide 400V.
 
Status
Not open for further replies.
Top