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. [Notes 1] Short-circuit inductance measurements are an alternative to, or complement of, open-circuit inductance measurements, and yield different approximations for the coupling factor and other derived quantities. Which measurement methodology is most relevant depends on the application.
Measured primary and secondary short-circuit inductances may be considered as constituent parts of primary and secondary self-inductances; they are related according to the coupling factor as,
- 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 , the inductive coupling factor and , the inductive leakage factor. is derived according to [Notes 2]:
- is the short-circuit measurement of primary or secondary inductance
- 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.
- Japan Industrial Standard C 5602-1986, pp 34, 4305
- This value is sometimes imprecisely referred to as leakage inductance
- the same k value can be obtained measured from the primary side or from the secondary side