Short-circuit inductance of a real linear two-winding
transformer
A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
is
inductance
Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The flow of electric current creates a magnetic field around the conductor. The field strength depends on the magnitude of the ...
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
Leakage inductance derives from the electrical property of an imperfectly-coupled transformer whereby each winding behaves as a self-inductance in series with the winding's respective ohmic resistance constant. These four winding constants also in ...
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,
:
:
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 , the inductive coupling factor and , the inductive leakage factor. is derived according to:[the same k value can be obtained measured from the primary side or from the secondary side]
:
where
:* 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
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillatin ...
of the magnetic phase synchronous coupling
Resonant inductive coupling or magnetic phase synchronous coupling is a phenomenon with inductive coupling where the coupling becomes stronger when the "secondary" (load-bearing) side of the loosely coupled coil resonates. A resonant transf ...
in a resonant transformer and wireless power transfer
Wireless power transfer (WPT), wireless power transmission, wireless energy transmission (WET), or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system ...
. Short-circuit inductance is the main component of the current-limiting parameter in leakage transformer applications.
See also
*Resonant inductive coupling
Resonant inductive coupling or magnetic phase synchronous coupling is a phenomenon with inductive coupling where the coupling becomes stronger when the "secondary" (load-bearing) side of the loosely coupled coil resonates. A resonant transfo ...
References
Notes
{{reflist, group=Notes
Electric transformers