440V Motor On A 480V Supply?
440V Motor On A 480V Supply?
(OP)
One of our clients specified 480Vac, 60Hz, nominal system voltage to feed their 440Vac, 60Hz motors.
Is there any concerns on this since the motors may be subjected to an almost 110% of nameplate voltage (assuming system is lightly loaded).
Is there any concerns on this since the motors may be subjected to an almost 110% of nameplate voltage (assuming system is lightly loaded).





RE: 440V Motor On A 480V Supply?
A standard NEMA motor should be good for continuous operation at 110% of nameplate. Even if the voltage at the MCC is 480V, the voltage at the motor will be less.
If these are old 440 V motors, they will probably be OK. They seem nearly indestructible sometimes.
David Castor
www.cvoes.com
RE: 440V Motor On A 480V Supply?
RE: 440V Motor On A 480V Supply?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 440V Motor On A 480V Supply?
The old standard (or I should say an old standard) for equipment voltages here in the US was 110 / 220 / 440, but was changed some time ago in an effort to standardize. Now the official equipment voltages are 115 / 200 / 230 / 460 and the distribution voltages are 120 / 208 / 240 / 480.
I laugh when I see new cheap motors come in from China with nameplates that say 220/440V, because it probably means they found some old design documents and built to them, without even bothering to find out that we don't use those values any longer.
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: 440V Motor On A 480V Supply?
RE: 440V Motor On A 480V Supply?
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: 440V Motor On A 480V Supply?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 440V Motor On A 480V Supply?
But certainly, anything 1965 and up is not "old" from my perspective...
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: 440V Motor On A 480V Supply?
I am still at limbo as to where this rating came from as far 480V nominal voltage application is concerned. I might raise this as a TQ later. I am wondering if these motors will work fine on 480Vac system consdering that their are near their maximum voltage threshold.
RE: 440V Motor On A 480V Supply?
Sounds like the customer has specified them and now already has them so they are likely stuck with them either used or still new.
RE: 440V Motor On A 480V Supply?
David Castor
www.cvoes.com
RE: 440V Motor On A 480V Supply?
This will figure why they allow 440V Motors on 480V system nominal. The next thing to do then is to keep an EYE on the vendor specifications to ensure this requirement is met.