3 Phase Generator Output - Electrician Talk - Professional Electrical Contractors Forum
 Electrician Talk - Professional Electrical Contractors Forum 3 Phase Generator Output
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 11-07-2018, 11:51 PM #1 Junior Member   Join Date: Nov 2018 Posts: 2 Rewards Points: 4 3 Phase Generator Output Could someone please confirm my understanding of 3 phase generators power output. I'm in Australia so all calculations are in 240v A 30kVA generator in total can provide a theoretical maximum of 30,000/240 = 125A which would be 41.6A per phase? Using a power factor or 0.8 we get a total of 125*0.8 = 100A or 33.3A per phase. So a 30kva generator is capable of running 3x32 amp distribution boxes? Cheers
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 11-07-2018, 11:57 PM #2 Senior Member   Join Date: May 2015 Location: Sacramento, California Posts: 14,057 Rewards Points: 26,360 In the real world, the alternator is loaded by real loads. Distribution boxes are NOT real loads. They are distribution nodes. You have to ask yourself: "What are the actual net loads to be served?" This calculation is termed a load-calc... what else? Set-up a spread sheet program and punch in the numbers. You'll want to look at actual Watts as well as keep an eye on Power Factor. ( If poor, the latter doesn't load up the alternator, but does figure in conductor sizing. ) Last edited by telsa; 11-08-2018 at 12:10 AM.
 11-08-2018, 12:20 AM #3 Junior Member   Join Date: Nov 2018 Posts: 2 Rewards Points: 4 Thanks So assuming unrealistic ideal loads I'm correct? Just after a sanity check that I'm not out by a factor of 3.

11-08-2018, 08:29 AM   #4
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Quote:
 Originally Posted by Beauc [COLOR=#212121][FONT=sans-serif]A 30kVA generator in total can provide a theoretical maximum of 30,000/240 = 125A which would be 41.6A per phase?
Huh?
__________________
I see nooothing, I was not here.
I did not even get up this morning.

11-08-2018, 01:43 PM   #5
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Quote:
 Originally Posted by Beauc A 30kVA generator in total can provide a theoretical maximum of 30,000/240 = 125A which would be 41.6A per phase? Using a power factor or 0.8 we get a total of 125*0.8 = 100A or 33.3A per phase. So a 30kva generator is capable of running 3x32 amp distribution boxes?

Quote:
 Originally Posted by Beauc Could someone please confirm my understanding of 3 phase generators power output.
I can confirm it is not correct. Are you an electrician? I don't see anything in your profile.

EDIT: I just realized I may be misreading this. Is the 240V L-L or L-N?

Last edited by AK_sparky; 11-08-2018 at 01:47 PM.

 11-08-2018, 03:36 PM #6 German Spy     Join Date: May 2014 Location: THE United States Of America Posts: 3,652 Rewards Points: 3,991 240v x 1.73 x 33.3a= @13KW brian john likes this. __________________ I see nooothing, I was not here. I did not even get up this morning.
 11-08-2018, 08:29 PM #7 Senior Member     Join Date: Mar 2007 Location: Gilbert's Corner VA Posts: 29,989 Rewards Points: 1,750 30X1000/240x1.732= 72.23 amps 30X.8/x1000/240X1.723= 57.78 amps or somewhere close to that __________________ Ah, but I was so much older then, I'm younger than that now Last edited by brian john; 11-08-2018 at 08:32 PM.

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