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Published transformer X/R ratios

Published transformer X/R ratios

Published transformer X/R ratios

(OP)
Does anyone know where I can find published X/R ratios for transformer especially those in the kVA range?  I looked in the IEEE Red Book and I only see a table for X/R ratios for transformers in the 1MVA range and higher and I was wondering if there was another reference that I am missing?

RE: Published transformer X/R ratios

(OP)
dpc

Thanks for the tables they are helpful!

Where does SKM reference its R and X values from?  For a 75kVA dry type transformer I cannot seem to match the values given to any one of the attached tables?

RE: Published transformer X/R ratios

(OP)
SKM gives a X/R ratio of about .875 for this 75kVA transformer.  This seems lower then the above publisehd information.

Isn't there an IEEE standard for transformers that would give all of these typical X/R values?

RE: Published transformer X/R ratios

Quote:

SKM gives a X/R ratio of about .875 for this 75kVA transformer.  This seems lower then the above publisehd information.
The X/R given in David's GE reference for a "QHT" 75 kVA dry type transformer (p.34) is 0.841.  Cuky's graph shows a 75 kVA dry type data point with an X/R between 0.5 and 1.  Seems like pretty good agreement to me.

RE: Published transformer X/R ratios

For SC calcs. , the X/R range of the published values provide acceptable results for most practical purposes.

If you are doing any special application, that require high level of accuracy, I suggest to obtain the actual data of the specific transformer and work with the manufactor and test lab.


 

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