A. Is increased
B. Is decreased
C. Remains the same
D. None od above
Answer with Explanation:
B. Is decreased
Explanation:
If you short the secondary you will get current that flows in both windings.
For the same voltage at the same frequency, the current will go up. Thus the impedance dropped.
Thus the measured inductance is smaller - smaller inductance is lower impedance, the opposite of capacitance.
If the secondary coil is shorted, the current in this coil is so directed that it opposes a change of flux.
Therefore the variation of the flux is much smaller, and so is the induced voltage in the primary coil.
When the secondary of the transformer is short-circuited, the primary inductance is decreased.
Electrical Fact
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
- What is the function of economizer in Thermal Power Plant
- Which of the following effects are associated with transmission line
- The insulator thickness on the conductor, in cables, depends upon
- By using a guard ring in a transmission line, its string efficiency
- If sag in an overhead line increase, the tension in the line
- Corona is accompanied by
- 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
- For Improving power factor
- 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
- Earth resistance in typical domestic wiring is
- 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.
- Shell Type Transformer is mainly used for
- A Magnetic Oil level Guage (MOG) is used in the Transformer to
- The Function Of Power Transformer is/are
- The Radiators are used in transformers for
Synchronous Motor MCQs With Explanation
- In 3 -Φ synchronous motor if one of the phases is short-circuited the motor will
- The speed regulation of a synchronous motor is
- The negative phase sequence in a three-phase synchronous motor exists when the motor is
- What happens if the field winding of the synchronous motor is short-circuited?
- For power factor correction, synchronous motors operate at