Question 1 of 28

1. What is the purpose of output transformer in inverters?

Step up AC from amplifier

Step down AC from amplifier

Step down input AC

Step up input AC

Question 1 of 28

Question 2 of 28

2. Which is the function of an inverter?

Converts D.C voltage into higher D.C voltage

Converts A.C voltage into D.C voltage

Converts D.C voltage into A.C voltage

Converts A.C voltage into higher A.C voltage

Question 2 of 28

Question 3 of 28

3. What is the type of A.C voltage stabilizer?

Servo voltage stabilizer

Automatic voltage stabilizer

Manual stepped voltage stabilizer

Constant voltage transformer stabilizer

Question 3 of 28

Question 4 of 28

4. Where square wave inverters are used?

DVD players

Computers

General lighting

TV receiver

Question 4 of 28

Question 5 of 28

5. Which is the cause for the fault if the output voltage of UPS is higher than normal?

Input voltage is very high

Battery get short circuited

Relay points are joined together

Defective feedback circuit

Question 5 of 28

Question 6 of 28

6. How the backup time of UPS can be increased?

Maintain battery terminal voltage always 90% of rating

Increase the VA rating of UPS

Decrease the AH capacity of battery

Increase the AH capacity of battery

Question 6 of 28

Question 7 of 28

7. Which feedback network is used for automatic voltage stabilizer?

Voltage divider network

Current divider network

Resistance temperature detector network

Tapped transformer network

Question 7 of 28

Question 8 of 28

8. Calculate the voltage and ampere/hour, if four cells rated as 1.5 V and 8 A.H are in parallel?

6 V and 24 AH

4.5 V and 8 AH

1.5 V and 32 AH

3 V and 16 AH

Question 8 of 28

Question 9 of 28

9. What is the reason for tripping the UPS with full load?

Main supply failure

Incorrect over load settings

Battery charger input fuse blown out

Loose connection in battery terminal

Question 9 of 28

Question 10 of 28

10. Which is frequency converter?

Rectifiers

D.C to A.C converters

Cyclo converters

D.C choppers

Question 10 of 28

Question 11 of 28

11. Which part in UPS supplies continuous output voltage in case of input voltage failure?

Inverter unit

Rectifier unit

Controller unit

Battery unit

Question 11 of 28

Question 12 of 28

12. What is the full form of PWM?

Phase Wide Modulation

Phase Width Modulation

Pulse Width Modulation

Pulse Wide Modulation

Question 12 of 28

Question 13 of 28

13. Which electronic circuit is used in an automatic voltage stabilizer to produce constant output voltage?

Oscillator circuit

Feedback circuit

Amplifier circuit

Rectifier circuit

Question 13 of 28

Question 14 of 28

14. What is the full form of UPS?

Unregulated Power Supply

Uniform Power Supply

Uninterrupted Power Supply

Universal Power Supply

Question 14 of 28

Question 15 of 28

15. What are the important stages in a simple inverter?

Oscillator and amplifier stages

Oscillator, amplifier and transformer output stages

Amplifier and transformer output stages

Oscillator and rectifier stages

Question 15 of 28

Question 16 of 28

16. Which principle the constant voltage transformer works?

Self induction principle

Ferro-resonant principle

Mutual induction principle

Fall in potential principle

Question 16 of 28

Question 17 of 28

17. How the hard sulphation defect in secondary cell can be prevented?

Provide freshening charge

Provide trickle charging

Provide constant current charging

Provide constant potential method charging

Question 17 of 28

Question 18 of 28

18. Which is the application of automatic stepped voltage stabilizer?

Pump motor

Television

Geyser

Grinder

Question 18 of 28

Question 19 of 28

19. What is the minimum permissible single phase working voltage, if the declared voltage is 240V as per ISI?

211 V

216 V

233 V

228 V

Question 19 of 28

Question 20 of 28

20. What is the effect in internal resistance of a discharged cell?

Becomes zero

Remain same

Decrease

Increase

Question 20 of 28

Question 21 of 28

21. Which instrument is used to check short circuit faults in electronic circuit in voltage stabilizer?

Voltmeter

Multimeter

Ohmmeter

Ammeter

Question 21 of 28

Question 22 of 28

22. What is the reason for having low back up time in UPS?

Ampere hour (A.H) capacity of battery is not sufficient

Mains earthing is not proper

Fault in inverter circuit

Battery is short circuited

Question 22 of 28

Question 23 of 28

23. Which electrical device is actuating the voltages in a stepped voltage stabilizer?

Output transformer

Autostat

Under voltage relay

Over voltage relay

Question 23 of 28

Question 24 of 28

24. What is the advantage of on-line UPS over offline UPS?

Supplies constant power output

Works on single phase or three phase supply

It gives constant output frequency

Free from change over and transition problems

Question 24 of 28

Question 25 of 28

25. Which type of output transformer is used in automatic voltage stabilizer?

Ferrite core type transformer

Auto transformer

Ring core type transformer

Static transformer

Question 25 of 28

Question 26 of 28

26. Which transformer is used in servo voltage stabilizer?

Step up transformer

Step down transformer

Toroidal autotransformer

Constant voltage transformer

Question 26 of 28

Question 27 of 28

27. Which term refers that the mass of a substance liberated from an electrolyte by one coulomb of electricity?

Electro plating

Electrolysis

Electro copying

Electro chemical equivalent

Question 27 of 28

Question 28 of 28

28. What is the effect during loading of the cell, the current strength falls and become zero?

Polarization

Buckling

Local action

Amalgamation

Question 28 of 28