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Anonymous Poster #1

Motor Rating

03/10/2014 9:28 AM

Hi Guys!

Why is it that motors are rated 460V which are used on a 480V nominal system voltage? Why not rate the motor at 480V?

Thanks.
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JRaef
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#1

Re: Motor Rating

03/10/2014 9:45 AM

480V is the "Distribution Voltage", 460V is the "Utilization Voltage", which allows for an expected voltage drop that will occur at the motor terminals by the time the distributed voltage gets to it through all the wires, connections and switching devices. For every Distribution Voltage there is a lower Utilization Voltage. For 240V it is 230V, for 120V it is 115V, for 208V it is 200V, for 4160V it is 4000V, etc. etc. etc. This is all laid out in ANSI specifications.

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giri
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#4
In reply to #1

Re: Motor Rating

03/11/2014 7:57 AM

What if the motor terminal voltage is 480V & even more than that by some +10% ?will it not harm the motor?It may seem a silly question,but please reply.

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4wsilver
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#5
In reply to #4

Re: Motor Rating

03/11/2014 10:53 AM

The voltage might be 480 or above when the motor isn't running but it will drop to a lower value when pulling a load.
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edsargento
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#8
In reply to #1

Re: Motor Rating

07/29/2015 11:43 PM

hi.

Apologies for this late reply.

Anyway, a bunch of thanks for this info. Appreciate it.

Have a good day fella...
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Fredski
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#2

Re: Motor Rating

03/10/2014 1:42 PM

same reason 120v AC motors work on 110v
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Delmar
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#3

Re: Motor Rating

03/10/2014 10:28 PM

Mr. Mom: yeah 220, 221 whatever it takes.

http://youtu.be/c6si8Xp8P-M

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HiTekRedNek
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#6

Re: Motor Rating

03/11/2014 3:16 PM

By design principles.A 10% overvoltage will not harm the motor, but a 10% undervoltage will harm it.Thus it is prudent to design for the lower voltage,because low voltage situations are more common.

As mentioned elsewhere, motor specs allow for this voltage drop from distribution to utilization voltage.

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edsargento
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#7
In reply to #6

Re: Motor Rating

03/11/2014 11:33 PM

Thank you for your comment...
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4wsilver (1); Delmar (1); edsargento (2); Fredski (1); giri (1); HiTekRedNek (1); JRaef (1)

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