University help: heavy equipment calculation

[BrandiLynn]

Hi, I'm an engineering student at Puerto Rico and I am doing a project on feeder calculation, the profesor added 3 phase large equipment, process units and heavy equipment. Does anubody know what that could be reffered to in the NEC? I need to determine the demand factors in order to calculate the feeder size and protection devices but I dont know what kind of equipment falls under these categories.

[ February 07, 2006, 02:53 PM: Message edited by: BrandiLynn ]

 

[charlie b]

Re: University help: heavy equipment calculation

Welcome to the Forum. I fear, however, that I do not understand the question.
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• <font size="2" face="Verdana, Helvetica, sans-serif">Are you asking how to calculate the feeder load? Is this an existing feeder to which you are adding three items, or is this a new feeder that will supply only those three items?</font>

<font size="2" face="Verdana, Helvetica, sans-serif"></font>

• <font size="2" face="Verdana, Helvetica, sans-serif">Are you asking about whether any demand factors or other factors (e.g., an extra 25% for motors) will apply to this feeder calculation?</font>

<font size="2" face="Verdana, Helvetica, sans-serif"></font>

• <font size="2" face="Verdana, Helvetica, sans-serif">Are you asking what section of the NEC applies to feeder calculations?</font>

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• <font size="2" face="Verdana, Helvetica, sans-serif">Are you asking something else entirely?</font>

<font size="2" face="Verdana, Helvetica, sans-serif">Can you please rephrase your question?

 

[BrandiLynn]

Re: University help: heavy equipment calculation

Hi, I'm an engineering student at Puerto Rico and I am doing a project on feeder calculation, the profesor added 3 phase large equipment, process units and heavy equipment. Does anubody know what that could be reffered to in the NEC? I need to determine the demand factors in order to calculate the feeder size and protection devices but I dont know what kind of equipment falls under these categories.

 

[charlie b]

Re: University help: heavy equipment calculation

It sounds like an industrial setting. So the "demand factors" part is easy: There is none. You count 100% of all three loads. If any of these items is a welder, then there is room to maneuver. If you can assert that they cannot all be running at the same time, then you might be able to take advantage of the "non-coincident load" article: 220.60.