Originally Posted by

**ish1284**
I'm not looking to test for the x/r of the reactor. I'm looking to determine if there is a standard for how series reactors are given their rating. Typically a standard of this nature would define a range for which the x/r ratio of the source used for testing needs to fall in. You can't stamp a rated let-thru on the equipment without knowing the 65kA source impedance and x/r ratio.

If you know the source x/r ratio that it was tested at, you can then calculate the source impedance (in terms of r and x) and then from there the only unknown variable in the equation would be the r of the reactor and it could be calculated. I was hoping for a workaround for calculating r of the reactor without having access to the test report.

you don't need the source x/r, only its Z

why do you need it anyways?

for SC calc of this nature Z is sufficient

from the data it can't be calculated

you know the Xl = 2 Pi 60 67 uH = 25.2584 1ph, 43.7488 3ph

you know total Z = 480/9415 = 50.9825 3ph

you know source Z = 480/65000 = 7.3846 mOhm 3ph

you know reactor Z = total - source = 43.5979

problem is reactor Xl > reactor Z

we can assume the 9415 includes X and R, since that is the reactor output

try another approach

system Vdrop at 9415 = 69.5262 v, so at reactor v = 410.4738

reactor i = 410.4738/43.5979 x 1000 = 9414.9912

current without reactor R = 480/(system Z + Xl) = 9387.2004 (lower since no R contribution)

new source vdrop = 9387.2004 x 7.3846/1000 = 69.3209 or 410.6791 at reactor

S = sqrt3 (9415 x 43.5979/1000) (9415) = 6693.7023 kva

Q = sqrt3 (9387.2004 x 43.7488/1000) (9387.2004) = 6677.2701 kvar

P = sqrt(6693.7023^2 - 6677.2701^2) = 468.7371

pf = 468.7371/6693.7023 = 0.0700, 85.9845 deg, x/r = 14.2453

R = 3.0711 mOhm

*The difference between genius and stupidity is that genius has its limits.*

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