Determining Power Transformer Size
- Thread starter bassil
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ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Determining Power Transformer Size
Whatever you calculate will be 2x what the utility will provide. You need to write a "load letter" to the utility for them to tell you what size they will give you.
Whatever you calculate will be 2x what the utility will provide. You need to write a "load letter" to the utility for them to tell you what size they will give you.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Re: Determining Power Transformer Size
I just noticed your occupation under your profile, good luck.
I just noticed your occupation under your profile, good luck.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: Determining Power Transformer Size
What do you mean by ?peak KVA requirements?? What type of facility are you addressing? Have you done an Article 220 load calculation, and are you interpreting its results as a ?peak? value?
A utility will provide a service transformer to a facility, based on the utility?s own process of calculating its required size. They will gladly take your load calculation results into account, but they will select the transformer by their own rules, and their own rules do not constrain them to follow the NEC. I am confident that their rules do take into account over a century?s worth of utility experience in placing transformers. Ron?s estimate of getting half what you tell them you need is a bit generous, I should think. I have seen utility transformers sized as low as 40% of the NEC calculated load.
What do you mean by ?peak KVA requirements?? What type of facility are you addressing? Have you done an Article 220 load calculation, and are you interpreting its results as a ?peak? value?
A utility will provide a service transformer to a facility, based on the utility?s own process of calculating its required size. They will gladly take your load calculation results into account, but they will select the transformer by their own rules, and their own rules do not constrain them to follow the NEC. I am confident that their rules do take into account over a century?s worth of utility experience in placing transformers. Ron?s estimate of getting half what you tell them you need is a bit generous, I should think. I have seen utility transformers sized as low as 40% of the NEC calculated load.
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