440v motor on 480v supply

tom baker

First Chief Moderator
Staff member
A motor for use on 480 is rated 460v. NEMA voltage tolerance is + - 5 % ( I think, it may be 10 %) the higher voltage can saturate the windings and increase amp draw.
 

Besoeker3

Senior Member
Location
UK
That's only 9% higher than nameplate. Not only will most motors tolerate that, you won't have the full 480 volts at the motor after all the voltage drops accumulate.
But you also have to take into account the tolerances on the 480V supply.
I wouldn't do it.
 

kwired

Electron manager
Location
NE Nebraska
That's only 9% higher than nameplate. Not only will most motors tolerate that, you won't have the full 480 volts at the motor after all the voltage drops accumulate.
Here no load volts is often near 500.

This probably a cheap motor to begin with, best to save $$ for a better replacement than to spend it on transformation;)

Light duty use, may still run a long time.
 

kwired

Electron manager
Location
NE Nebraska
And that on a 440V motor...................
Question is whether it truly is rated 440 volts, or is it intended to operate on 416 as well as 480? That does land about in the middle of that range.

Though places with 416 are usually 50 Hz so that idea isn't so good either.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
our 277-480 tends to hover around 495-500V no load. That’s only 4% voltage rise, but it’s about 13% higher than the motors rating.

Depending on your situation and where you are, the transformer could have taps and you could get the voltage lowered by 2.5% if needed.
will it work? Sure. How long?

I would definitely check the no load voltage.


Here’s some data on that motor.
http://www.teco.com.tw/fa/ecatalogue_file/en/HighEfficiencyMotor-AEHL-AEUL0710.pdf
 

kwired

Electron manager
Location
NE Nebraska
our 277-480 tends to hover around 495-500V no load. That’s only 4% voltage rise, but it’s about 13% higher than the motors rating.

Depending on your situation and where you are, the transformer could have taps and you could get the voltage lowered by 2.5% if needed.
will it work? Sure. How long?

I would definitely check the no load voltage.


Here’s some data on that motor.
http://www.teco.com.tw/fa/ecatalogue_file/en/HighEfficiencyMotor-AEHL-AEUL0710.pdf
From your link

Voltages - 220 V, 380 V, 400 V, 460 V or Daul Voltage.

I guess OP's is dual voltage with 220 being one of the two. Still possible this wasn't exactly intended to be used on 480 volts nominal, probably will work though but for how long?
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
From your link

Voltages - 220 V, 380 V, 400 V, 460 V or Daul Voltage.

I guess OP's is dual voltage with 220 being one of the two. Still possible this wasn't exactly intended to be used on 480 volts nominal, probably will work though but for how long?
My question exactly...
 

Besoeker3

Senior Member
Location
UK
Question is whether it truly is rated 440 volts, or is it intended to operate on 416 as well as 480? That does land about in the middle of that range.

Though places with 416 are usually 50 Hz so that idea isn't so good either.
Actually, the EU zone is now "harmonised" at 400V, 50Hz.
 

powerpete69

Senior Member
Location
Northeast, Ohio
Occupation
Professional Electrical Engineer
The answer is highly questionable. May want to consider using a 480V to 440V transformer with adjustable secondary taps. Looks like 25KVA would be correct size. Motors dislike it when you change their intended voltage.

Consider the cost of that transformer vs the cost of a new motor. If the cost of a new properly sized 480V motor is less then the cost of transformer, go ahead and try the 440V motor. If the 440V motor fails, install the new 480V motor.

If cost of transformer is less than the cost of a new 480V motor, go ahead and install the correct transformer and all should work well.
 

Besoeker3

Senior Member
Location
UK
The answer is highly questionable. May want to consider using a 480V to 440V transformer with adjustable secondary taps. Looks like 25KVA would be correct size. Motors dislike it when you change their intended voltage.

Consider the cost of that transformer vs the cost of a new motor. If the cost of a new properly sized 480V motor is less then the cost of transformer, go ahead and try the 440V motor. If the 440V motor fails, install the new 480V motor.

If cost of transformer is less than the cost of a new 480V motor, go ahead and install the correct transformer and all should work well.
It isn't a big change in voltage nor do I see the need for electrical isolation. So, compared to the motor rating, the transformer would have a relatively low kVA rating.
But then you have installation costs for additional installation and cabling.
Get the right motor instead of faffing about. It isn't as if it is a big motor.

Just an aside, I have nothing against TECO. We have used their motors, most likely on pumping projects, and I have now recollection of any problems.
I spent eight months in Taiwan and sas lots of them. I believe Taiwan Electrical Manufacturing Company is how it was Anglicised.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor

Besoeker3

Senior Member
Location
UK
I say yes, and likewise for the motor in the OP, as long as there is no frequency disparity.

We've discussed this before, but this is the first time there's been a won't-work bent about it.
If your 480V supply has a 5% tolerance it could be 504V.
Thus 14.5% above the 440V rating of the motor.
The TECO datasheet kindly provided by an earlier poster shows the motor voltage range as ±10%.
so would it work? Possibly.
Would it invalidate warranty? Probably.

Does it matter? Is it worth the risk?
Depends on the application.

A little vaguely related tale.
I was having a cup of tea in the electrician's shop in a paper mill. Typical hurry up and wait scenario. I noticed a notice on the wall.
"An hour of down time costs £4,700."
That was in December 1979.
 
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