Help with basic(?) math

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NoobLookingForInfo

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Trying to figure out some basics regarding a project I am just starting to get into, so I figured I would look to an electricity forum in hopes of getting some preliminary answers.


If I have a 1600amp, 600v 3 phase entrance, when we break that down into 240v lines, is there some kind of formula that would help me to determine how much total amperage we would have to work with? If I wanted to use 75% of the total amperage @ 240v, installing machines that each draw 6.5 amps, is it possible to figure out what the total number of units we could potentially install?


Please excuse my ignorance if I made some glaring mistakes. Electricity is still a work in progress for me. Thank you.
 
roger

roger

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NoobLookingForInfo said:
Trying to figure out some basics regarding a project I am just starting to get into, so I figured I would look to an electricity forum in hopes of getting some preliminary answers.


If I have a 1600amp, 600v 3 phase entrance, when we break that down into 240v lines, is there some kind of formula that would help me to determine how much total amperage we would have to work with? If I wanted to use 75% of the total amperage @ 240v, installing machines that each draw 6.5 amps, is it possible to figure out what the total number of units we could potentially install?


Please excuse my ignorance if I made some glaring mistakes. Electricity is still a work in progress for me. Thank you.
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Since this isn't a normal DIY (how to install) type question we will allow it for discussion, however let's remeber the rules,

This site is designed for:


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* This NEC� Forum is for those in the electrical and related industries. Questions of a "How-To" nature by persons not involved in the electrical industry will be removed without notice.

Knowledge and the practical application of the National Electrical Code is an essential part of all electrical installations. If it's important for you to understand the National Electrical Code, then look no further.
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​Roger
 
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GoldDigger

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NoobLookingForInfo said:
Trying to figure out some basics regarding a project I am just starting to get into, so I figured I would look to an electricity forum in hopes of getting some preliminary answers.


If I have a 1600amp, 600v 3 phase entrance, when we break that down into 240v lines, is there some kind of formula that would help me to determine how much total amperage we would have to work with? If I wanted to use 75% of the total amperage @ 240v, installing machines that each draw 6.5 amps, is it possible to figure out what the total number of units we could potentially install?


Please excuse my ignorance if I made some glaring mistakes. Electricity is still a work in progress for me. Thank you.
Click to expand...

First, you will not "break 600V down into 240V lines without using transformers. This will have a small, but noticeable power loss.
Second, are your 6.5A machines single phase or three phase?
Finally, does your environment require a grounded neutral conductor (will determine transformer configuration.)

The simple way to do the math is to calculate the kVA available from the service and then calculate the kVA used by each machine, then assume that you can balance the load over all three phases.
 
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NoobLookingForInfo

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Location
Canada
There are already multiple transformers in place. One for 120, one for 240 and there was a 3rd for a higher voltage. It is a large, abandoned manufacturing space, almost 200k square feet. The machines themselves are single phase, 1200w.

I'm just trying to get a vague guesstimate on the number of machines it would be possible to put inside using that type of entrance, regardless of whether or not we would need to add/subtract/change out the current configuration to optimize it.
 
N

NoobLookingForInfo

Member
Location
Canada
GoldDigger said:
First, you will not "break 60V down into 240V lines without using transformers. This will have a small, but noticeable power loss.
Second, are your 6.5A machines single phase or three phase?
Finally, does your environment require a grounded neutral conductor (will determine transformer configuration.)

The simple way to do the math is to calculate the kVA available from the service and then calculate the kVA used by each machine, then assume that you can balance the load over all three phases.
Click to expand...

Ok, does this make sense at all?

The kVa of a 1600amp, line to line entrance = 1662 (https://www.rapidtables.com/calc/electric/Amp_to_kVA_Calculator.html)
the kVa of a 1200w PSU = 1.5 (http://www.dieselserviceandsupply.com/Power_Calculator.aspx#kwtokva)

So at the very basic, simplistic level the math would be 1662/1.5 = 1100'ish.

Sorry for spamming, I dont see an option to edit my other post.
 
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gar

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Roughly speaking you have an input VA rating of 1600*600/1.732 per phase or 554,000 VA or 554 kVA. Multiply by 3 and this is 1662 kVA. This assumes that your 1600 is the per line current, and that 600 is line to line voltage.

At 240 V this is a total current of 6925 A.

A simpler quicker way is 1600*1.732*600/240 = 6928 .

Using 75% of the current is 5196 A. At 240 V and 6.5 A, then you can have 5196/6.5 = 799 machines.

There might be other considerations.

Why the 1.732 constant which is the sq-root of 3? If you really wanted to know, then it could be discussed.

.
 
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