I am just trying to understand how to get the correct Buck-Boost Transformer. Do I take the current on the nameplate times the rated valtage, which equals the VA rating and divide that by 1000 to get my KVA's. Then this is the size transformer I need. Example would 17amps X 240v = 4080VA, then divide this by 1000 = 4.08. So I would need about 4KVA buck-boost transformer. I reason I ask because in another post on this subject there another reply that said take 240v-208 =32v, then 32v x 17a = 544va and said that you would need a 1 kva. Could someone explain the correct way to size a buck to boost. I am just trying to learn something here. I know I can just ask the guy that front desk and he can look it up in his book but I would like to know. Thanks
Buck-Boost Transformers
- Thread starter guschash
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- PE (Retired) - Power Systems
The way to size any transformer in kVA is basically to multiply Volts x Amps and divide by 1000.
A buck-boost transformer looks like a special condition. Because of the way it functions as an auto-transformer it appears we are only concerned with the difference in the voltages, hence your example of 240V-208V=32V.
The reality is that we are doing nothing special, a buck-boost transformer has a secondary voltage that gets added to the primary voltage. So, the result is that we use standard formulas to size the transformer based on the secondary V not the total voltage.
A buck-boost transformer looks like a special condition. Because of the way it functions as an auto-transformer it appears we are only concerned with the difference in the voltages, hence your example of 240V-208V=32V.
The reality is that we are doing nothing special, a buck-boost transformer has a secondary voltage that gets added to the primary voltage. So, the result is that we use standard formulas to size the transformer based on the secondary V not the total voltage.
yankj
Senior Member
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- Carrollton, Texas
What Jim is saying is you only account for the amount of VA that you are boasting (say 32V X A) not the total when sizing buck-boast.
Here is a great link for understanding Buck boost Xfmers
http://www.powertransformer.us/acmebuckboosttransformers.htm
http://www.powertransformer.us/acmebuckboosttransformers.htm
winnie
Senior Member
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- Springfield, MA, USA
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- Electric motor research
Generally for such a small application you would round up rather than down.
-Jon
-Jon
I ran across that same article on Acme's website. It's out of their catalogue. Here's a link to the pdf: http://www.acmepowerdist.com/pdf/Page_104-109.pdf
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