This set of Power Electronics Multiple Choice Questions & Answers (MCQs) focuses on “Applications of Power Electronics-1”.
1. SMPS is used for
a) obtaining controlled ac power supply
b) obtaining controlled dc power supply
c) storage of dc power
d) switch from one source to another
Explanation: SMPS (Switching mode power supply) is used for obtaining controlled dc power supply.
2. SPMS are based on the ________ principle.
a) Phase control
b) Integral control
Explanation: SMPS (Switching mode power supply) are based on the chopper principle. The output dc voltage is controlled by varying the duty cycle of the chopper circuit.
3. Choose the incorrect statement.
a) SMPS is less sensitive to input voltage variations
b) SMPS is smaller as compared to rectifiers
c) SMPS has low input ripple
d) SMPS is a source of radio interference
Explanation: SMPS has higher output ripple and its regulation is worse.
4. _________ is used for critical loads where temporary power failure can cause a great deal of inconvenience.
Explanation: Uninterruptible Power Supply is used where loads where temporary power failure can cause a great deal of inconvenience.
5. __________ is used in the rotating type UPS system to supply the mains.
a) DC motor
b) Self excited DC generator
d) Battery bank
Explanation: When the supply is gone, the diesel engine is started, which runs the alternator and the alternator supplies power to the mains. Non-rotating type UPS are not used anymore.
6. Static UPS requires __________
a) only rectifier
b) only inverter
c) both inverter and rectifier
d) none of the mentioned
Explanation: Rectifier to converter the dc from the battery to ac. Inverter to charge the battery from mains.
7. No discontinuity is observed in case of
a) short break static UPS configuration
b) long break static UPS configuration
c) no break static UPS configuration
d) rotating type UPS configuration
Explanation: No dip or discontinuity is observed in case of no break static UPS configuration, as the battery inverter set immediately takes over the mains.
8. Usually __________ batteries are used in the UPS systems.
c) Lead acid
d) All of the mentioned
Explanation: Lead acid batteries are cheaper and have certain advantages over the other types. NC batteries would however be the best, but are three to four times more expensive than Lead Acid.
9. HVDC transmission has ___________ as compared to HVAC transmission.
a) smaller transformer size
b) smaller conductor size
c) higher corona loss
d) smaller power transfer capabilities
Explanation: The conductor size is smaller as there is no sink effect, and the whole conductor is utilized for transmitting power.
10. The negative polarity is used in the monopolar link because it
a) uses less conductor size
b) is safer
c) produces less radio interference
d) has less resistance
Explanation: The monopolar link uses just a single conductor, which is usually negative as it produces less radio interference and corona.
Sanfoundry Global Education & Learning Series – Power Electronics.
To practice all areas of Power Electronics, here is complete set of 1000+ Multiple Choice Questions and Answers.