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Gremlin
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Homework Statement
A 415V to 11 kV transformer has a rating of 200 kVA. The winding resistance and leakage reactance when referred to the primary are 0.014 Ω and 0.057 Ω respectively.
(b) In designing a particular 415V to 11 kV, 200 kVA transformer, the primary winding resistance is to be 10 mΩ. Find the maximum winding resistance of the secondary winding if the transformer is to have 2% regulation at unity power factor.
Homework Equations
Voltage Regulation ≈ (VA Rating / V12) x R'p x 100
n = N1 / N2 = E1 / E2
R'p = Rp x n2 Rs
The Attempt at a Solution
Voltage Regulation = 2%
VA Rating = 200000
V1 = 415
V2 = 11000
Rp = 0.01
Cosθ = 1
2 ≈ (200000 / 4152) x R'p x 100
2/100 ≈ 1.161271 x R'p
0.02 / 1.161271 ≈ R'p
R'p ≈ 0.01722
E1 / E2 = 415/11000 = 0.037727
0.01722 = 0.01 x 0.0377272 x Rs
0.01722 / 1.42333 x 10-3 = Rs
Rs = 1209.84Ω
I'm sure I'm wrong, but am i in the correct ball park in the way I'm going about answering the question?
Thanks.