Short-circuit Inductance

Short-circuit inductance of a real linear two-winding transformer is inductance measured across the primary or secondary winding when the other winding is short-circuited.Japan Industrial Standar
C 5602-1986, pp 34, 4305
/ref>This value is sometimes imprecisely referred to as leakage inductance　
The method of measuring the short circuit inductance is described in industrial standard. The industrial standard also stipulates a method for obtaining the coupling factor by combining it with the open circuit inductance value.

Measured primary and secondary short-circuit inductances may be considered as constituent parts of primary and secondary self-inductances. They are derived by using Ho-Thevenin's theorem from the equivalent inductance of the three-terminal equivalent circuit as follows. Then they are related according to the coupling factor as,

:$L_ = (1-k^2)\cdot L_\,$
:$L_ = (1-k^2)\cdot L_\,$
Where
:*k is coupling coefficient
:*L₁ is primary self-inductance
:*L₂ is secondary self-inductance

Short-circuit inductance measurement is used in conjunction with open-circuit inductance measurements to obtain various derived quantities like $k$, the inductive coupling factor and $\sigma$, the inductive leakage factor. $k$ is derived according to:the same k value can be obtained measured from the primary side or from the secondary side

:$k = \sqrt$
where
:*$L_\text$ is the short-circuit measurement of primary or secondary inductance
:*$L_\text$ is the corresponding open-circuit measurement of primary or secondary inductance

Other transformer parameters like leakage inductance and mutual inductance which cannot be directly measured may be defined in terms of k.

Short-circuit inductance is one of the parameters that determines the resonance frequency of the magnetic phase synchronous coupling in a resonant transformer and wireless power transfer. Short-circuit inductance is the main component of the current-limiting parameter in leakage transformer applications.

See also

*Resonant inductive coupling

References

Notes

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Electric transformers