TRANSFORMER SHORT CIRCUIT TEST

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panthripu

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Why short circuit test on transformer can not separate out the primary and secondary resistances and leakage reactance ?
 

Julius Right

Senior Member
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Electrical Engineer Power Station Physical Design Retired
Since primary and secondary windings are connected magnetically you cannot separate the reactances. We can measure d.c. resistance separately but not a.c. resistance [no skin effect and proximity effect in d.c.].

The no-load impedance is the total primary impedance including leakage reactance [Xp] and main magnetic flux reactance [Xm] and the primary winding resistance [Rp].

Measuring no-load losses and load losses we may calculate the sum of a.c. resistance of both sides [Rp+R's] including core losses and tank losses -if any [Rfe].

Why cannot separate impedances.jpg
 

GoldDigger

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Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Another way of looking at it is that we are connecting only to two terminals and can vary voltage and measure current. That gives us one complex impedance. You cannot make that give you three separate numbers, only two.

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