While conducting open circuit test and short circuit test on a transformer, status of low voltage and high voltage windings will be such that in ____________
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Correct AnswerA. OC test − h.v. open, SC test − l.v. short-circuited
Quick Explanation
In the usual transformer tests, the open-circuit test is performed by energizing the LV side and leaving the HV side open. The short-circuit test is usually performed by shorting the LV side and applying a reduced voltage to the HV side. This matches option A.
Formula / Key Relation
OC test:
LV energized at rated voltage
HV open
SC test:
LV short-circuited
Reduced voltage applied to HV until rated current flows
Detailed Explanation
Concept & ReasoningThe OC test needs rated voltage but only a small no-load current. Supplying the LV winding is convenient and safer for instruments, while the HV winding is left open. The SC test needs only a small fraction of rated voltage but full-load current. The LV winding is commonly shorted and the reduced test voltage is applied to the HV winding so that the current on the HV side is smaller and easier to measure. The exact side chosen can be changed in practice, but the standard exam convention is the one stated in option A.How to Solve It…
Concept & Reasoning
The OC test needs rated voltage but only a small no-load current. Supplying the LV winding is convenient and safer for instruments, while the HV winding is left open. The SC test needs only a small fraction of rated voltage but full-load current. The LV winding is commonly shorted and the reduced test voltage is applied to the HV winding so that the current on the HV side is smaller and easier to measure. The exact side chosen can be changed in practice, but the standard exam convention is the one stated in option A.
How to Solve It in the Exam
OC: open HV. SC: short LV (standard laboratory convention).
Important Exam Point
Focus on why instruments are conveniently connected to the chosen side.
Related Revision Path
This question sits in the revision path Electrical Machines → Transformers → OC and SC Tests .
Quick Trick
OC: open HV. SC: short LV (standard laboratory convention).
Common Mistake
Do not confuse which side is energized with which side is open/shorted.
Exam Tip
Focus on why instruments are conveniently connected to the chosen side.
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