Question 1 of 28

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

216 V

233 V

228 V

211 V

Question 1 of 28

Question 2 of 28

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

Increase

Becomes zero

Remain same

Decrease

Question 2 of 28

Question 3 of 28

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

Voltage divider network

Tapped transformer network

Resistance temperature detector network

Current divider network

Question 3 of 28

Question 4 of 28

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

Loose connection in battery terminal

Incorrect over load settings

Main supply failure

Battery charger input fuse blown out

Question 4 of 28

Question 5 of 28

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

Supplies constant power output

Works on single phase or three phase supply

Free from change over and transition problems

It gives constant output frequency

Question 5 of 28

Question 6 of 28

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

Electro chemical equivalent

Electrolysis

Electro copying

Electro plating

Question 6 of 28

Question 7 of 28

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

Grinder

Television

Pump motor

Geyser

Question 7 of 28

Question 8 of 28

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

Constant voltage transformer stabilizer

Automatic voltage stabilizer

Manual stepped voltage stabilizer

Servo voltage stabilizer

Question 8 of 28

Question 9 of 28

9. What is the full form of PWM?

Phase Wide Modulation

Pulse Width Modulation

Pulse Wide Modulation

Phase Width Modulation

Question 9 of 28

Question 10 of 28

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

Ferrite core type transformer

Ring core type transformer

Static transformer

Auto transformer

Question 10 of 28

Question 11 of 28

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

Ammeter

Ohmmeter

Voltmeter

Multimeter

Question 11 of 28

Question 12 of 28

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

4.5 V and 8 AH

3 V and 16 AH

1.5 V and 32 AH

6 V and 24 AH

Question 12 of 28

Question 13 of 28

13. What is the full form of UPS?

Unregulated Power Supply

Uniform Power Supply

Uninterrupted Power Supply

Universal Power Supply

Question 13 of 28

Question 14 of 28

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

Oscillator and rectifier stages

Amplifier and transformer output stages

Oscillator and amplifier stages

Oscillator, amplifier and transformer output stages

Question 14 of 28

Question 15 of 28

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

Battery get short circuited

Defective feedback circuit

Relay points are joined together

Input voltage is very high

Question 15 of 28

Question 16 of 28

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

Autostat

Under voltage relay

Output transformer

Over voltage relay

Question 16 of 28

Question 17 of 28

17. Which principle the constant voltage transformer works?

Self induction principle

Fall in potential principle

Mutual induction principle

Ferro-resonant principle

Question 17 of 28

Question 18 of 28

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

Step up input AC

Step up AC from amplifier

Step down AC from amplifier

Step down input AC

Question 18 of 28

Question 19 of 28

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

Polarization

Buckling

Local action

Amalgamation

Question 19 of 28

Question 20 of 28

20. Which is the function of an inverter?

Converts A.C voltage into higher A.C voltage

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

Question 20 of 28

Question 21 of 28

21. Which transformer is used in servo voltage stabilizer?

Step down transformer

Toroidal autotransformer

Constant voltage transformer

Step up transformer

Question 21 of 28

Question 22 of 28

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

Feedback circuit

Oscillator circuit

Rectifier circuit

Amplifier circuit

Question 22 of 28

Question 23 of 28

23. Where square wave inverters are used?

Computers

General lighting

TV receiver

DVD players

Question 23 of 28

Question 24 of 28

24. Which is frequency converter?

D.C choppers

Cyclo converters

Rectifiers

D.C to A.C converters

Question 24 of 28

Question 25 of 28

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

Battery unit

Rectifier unit

Inverter unit

Controller unit

Question 25 of 28

Question 26 of 28

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

Increase the AH capacity of battery

Increase the VA rating of UPS

Decrease the AH capacity of battery

Maintain battery terminal voltage always 90% of rating

Question 26 of 28

Question 27 of 28

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

Provide freshening charge

Provide constant potential method charging

Provide constant current charging

Provide trickle charging

Question 27 of 28

Question 28 of 28

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

Battery is short circuited

Fault in inverter circuit

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

Mains earthing is not proper

Question 28 of 28