A. Short Circuit Test
B. Open Circuit Test
C. Both A & B
D. None of the Above
Answer
A. Short Circuit Test
Explanation
- Copper loss in the transformer is measured by the short-circuit test of the transformer. For measuring copper loss first we short-circuit the transformer low voltage side. After the short circuit of LVS, a small voltage is applied on the H.V side till the rated current flow in the L.V side.
- Short-circuit test is carried out at rated current to determine the full load copper loss.
- Since the transformer winding resistance is not affected much by frequency in the power frequency range this test need not be necessarily conducted at the rated frequency.
- This test is carried out with the instruments placed on the high voltage side while the low voltage side is short-circuited by a thick conductor.
- This is because the rated current on the high voltage side is lower than on the low voltage side and therefore economic instruments may be used.
- A short circuit test is used to determine the copper losses and an open circuit test is used to determine the core losses.
- Open circuit test is carried out on the low voltage side while the high voltage side is open-circuited.
Power System MCQs With Explanation
- The advantages of high transmission voltage are
- The charging current drawn by the cable is
- The fact that current density is higher at the surface when compared to the center is known as
- In which of the following transmission lines capacitance effect is negligible?
- The distribution constant of the transmission line is
- Proximity effect is more in case of
- If the frequency is increased, then the skin effect will
- Bundled conductors in EHV transmission lines help in
- Which of the following produces radio interference in communication lines?
- Telecommunication lines are transposed to reduce the
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- By using a guard ring in a transmission line, its string efficiency
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- The conductor carries more current on the surface as compared to the core. This is called as
- Critical disruptive voltage is a voltage at which
- Bundled conductors are used for EHV transmission lines primarily for reducing the
- Low power factor is usually not due to
- Bonding is done at both ends of the cable to reduce the
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- Stock bridge dampers are used to
- Which of the following insulator is practically used for railway crossings?
- Which of the following decides the insulation level of 400 kV, EHV line?
- When earth fault occurs
- The minimum length of pipe electrode used for earthing should not be less than
- A ground wire is used to
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- By which of the following systems electric power may be transmitted?
- Which of the following equipment will be most economical for regulating the voltage in the distribution feeder?
Transformer MCQs With Explanation
- In a transformer the primary flux is
- The noise of the transformer is mainly due to
- Buchholz relay is used for the protection
- Iron loss in a transformer can be determined by
- Oil is provided in an oil-filled transformer for
- In a star-delta transformer, the delta side phase voltage leads the star sides phase voltage by an angle
- Minimum voltage regulation occurs in transformer when the power factor of the load is
- The chemical used in the breather of a transformer should have the property of
- The power transformer can be termed as a constant
- In a transformer, which of the following losses are zero?
- Which of the following Transformer can have a tap changer?
- If the supply frequency (f) of a transformer decreases, the effect of frequency on the transformer's secondary output voltage?
- The primary winding of a transformer has a 120 V ac supply. What is the value of secondary voltage if the turn ratio is 10?
- The efficiency of a power transformer is _____ at full load.
- In a transformer the relation between the input frequency and the output voltage on secondary winding is _____.
- In a current transformer, _____ winding is closed.
- A transformer is a _____ device.
- A step-down transformer has _____ number of turns on primary winding and _____ number of turns on the secondary winding.
- A step-up transformer has _____ number of turns on primary winding and _____ number of turns on the secondary winding.
- Transformer works on ______ principle.
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- The Function Of Power Transformer is/are
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Synchronous Motor MCQs With Explanation
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