# 3 phase calculations.



## K2500 (Mar 21, 2009)

knowledge29 said:


> Hi guys, I have a 3phase sub panel and I need help figuring out the most efficient way to find out how much current is being consumed.Thanks for the help...Its a 3phase 120/208 being fed from a 480/3phase 100amp panel...


Power is consumed, current is not.

Either;
turn every thing on and do a current measurement,
find each individual load and do a load calculation,
use a recording power meter for a number of days.

Why do you need this information? Are you planning on adding an additional load to this panel?


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## Cletis (Aug 20, 2010)

*Product*

Try these. They are great

http://www.emon.com/products.html


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## knowledge29 (Nov 6, 2010)

yes,I am planning on installing a 17hp vac systems for a cnc router.


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## electures (Oct 23, 2008)

knowledge29 said:


> Hi guys, I have a 3phase sub panel and I need help figuring out the most efficient way to find out how much power is being consumed.Thanks for the help...Its a 3phase 120/208 being fed from a 480/3phase 100amp panel...


Amprobe it or calculate the load.


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## tgreen (Sep 14, 2010)

if you dont know the calculated load of the panel based upon all the connected load, then you should get a recording meter and test it for 30 days to find max and average load.


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## l0sts0ul (May 7, 2011)

tgreen said:


> if you dont know the calculated load of the panel based upon all the connected load, then you should get a recording meter and test it for 30 days to find max and average load.


 
A power quality meter would be best yes, however, if this is your only panel in the plant or site, you could call the power company and they can give you a 12 month readout of consumption, PF, and any 3rd harmonics you might be dealing with. Depending on the PF of the Vac, you might want to consider some PFC to reduce your inductive load a little, and reduce long term power costs.

just my 2c


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## alfie1984 (May 11, 2011)

remember to carry the 1 :thumbsup:


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## bobelectric (Feb 24, 2007)

knowledge29 said:


> Hi guys, I have a 3phase sub panel and I need help figuring out the most efficient way to find out how much power is being consumed.Thanks for the help...Its a 3phase 120/208 being fed from a 480/3phase 100amp panel...


 It will go "Blooowey"


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## johnsmithabe (May 3, 2011)

Why u r installing? Wats ur purpose?


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## tgreen (Sep 14, 2010)

Bob had a good catch on this, i didnt even see that they were feeding a 208 panel from a 480 panel. 

I guess im just used to speaking with professionals all day,


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