Size Transfomers required for 1200 120 240 3 phase service
Size Transfomers required for 1200 120 240 3 phase service
(OP)
A small but welcomed reply would be most helpful in this matter!
According to my calculations, the size transfomers required for a 120 - 240 volt 3 phase service of 1200 amps (max rated load) should be three (3) 167 KVA transfomers!
Now if I consider 80% of full load (960 amps)I will wind up with appx a 133 kva rating for a set of transfomers. This will not be possible In as much as they don't make any pole mount transfomers in between 100 kva and 167 kva unless special ordered or in three phase padmount confuguration.
Anyway, I would like to check my figures to see if I am right! Thanks
According to my calculations, the size transfomers required for a 120 - 240 volt 3 phase service of 1200 amps (max rated load) should be three (3) 167 KVA transfomers!
Now if I consider 80% of full load (960 amps)I will wind up with appx a 133 kva rating for a set of transfomers. This will not be possible In as much as they don't make any pole mount transfomers in between 100 kva and 167 kva unless special ordered or in three phase padmount confuguration.
Anyway, I would like to check my figures to see if I am right! Thanks






RE: Size Transfomers required for 1200 120 240 3 phase service
RE: Size Transfomers required for 1200 120 240 3 phase service
RE: Size Transfomers required for 1200 120 240 3 phase service
RE: Size Transfomers required for 1200 120 240 3 phase service
RE: Size Transfomers required for 1200 120 240 3 phase service
You may want to review consensus standards for applicability.
IEEE Std C57.91-1995 Guide for Loading Mineral-Oil-Immersed Transformers, or
IEEE Std C57.96-1999 Guide for Loading Dry-Type Distribution and Power Transformers
RE: Size Transfomers required for 1200 120 240 3 phase service
In the US, every utility has localized practices, but a usual breakpoint for 240- versus 480-volt service is 30-60hp / 30-60kVA. Conductor and switchgear expense gets progressively more expensive for the lower voltage. A classic text on electrical design is D Beeman, Industrial Power Systems Handbook, McGraw-Hill, 1955.
Offhand, the relative expense of a 277- versus 240-volt transformer is probably negligible.
RE: Size Transfomers required for 1200 120 240 3 phase service
The lighting and HVAC stuff and receptacles for maintenance and office type usage would probably most likely be okay at 120/208v 3ph 4w. What I have done in the past for factories that required 230V, or whatever... is calculate the amount of load required at the non standard voltage... and have a separate transformer and sub electrical distribution and panels, etc., inside the building serving that specific equipment. The rest of the electrical equipment... like fans and lighting and receptacles, etc., etc., I would feed off of distributions at standard voltages... which in my area are 120/208v 3ph 4w and 347/600v 3ph 4w.
That way you could have standard type pole mounted transformers for your area... and just specify one, or maybe two relatively smaller sized transformers at 120/240v 3ph.
You also could being saving yourself the bother of trying to get 240v 3ph HVAC equipment and pumps, etc.
Margaret
RE: Size Transfomers required for 1200 120 240 3 phase service
I guess sometimes I just worry too much about our system! Anyway again, thanks!
RE: Size Transfomers required for 1200 120 240 3 phase service