UPS (Uninterruptible Power Supplies) MCQs

Q1: What is the primary function of a UPS?
(A) To increase voltage levels
(B) To provide backup power during outages
(C) To regulate the temperature of electronic devices
(D) To convert AC to DC power
Answer: (B) To provide backup power during outages

Q2: Which of the following is NOT a component of a UPS system?
(A) Battery
(B) Inverter
(C) Cooling fan
(D) Oscilloscope
Answer: (D) Oscilloscope

Q3: A UPS protects connected devices from which of the following power issues?
(A) Voltage surges
(B) Power outages
(C) Voltage sags
(D) All of the above
Answer: (D) All of the above

Types of UPS

Q4: Which type of UPS is most commonly used for small office setups?
(A) Online UPS
(B) Line-interactive UPS
(C) Standby UPS
(D) Double-conversion UPS
Answer: (C) Standby UPS

Q5: In an online UPS, the load is powered by the __________ under normal conditions.
(A) AC mains
(B) Battery
(C) Inverter
(D) Transformer
Answer: (C) Inverter

Technical Aspects

Q6: What is the role of an inverter in a UPS system?
(A) To convert AC to DC
(B) To charge the battery
(C) To convert DC to AC
(D) To regulate power frequency
Answer: (C) To convert DC to AC

Q7: What determines the runtime of a UPS system?
(A) Battery capacity
(B) Input voltage
(C) Load on the UPS
(D) Both A and C
Answer: (D) Both A and C

Performance

Q8: Which of the following is the typical efficiency range of an online UPS?
(A) 50-60%
(B) 70-80%
(C) 90-95%
(D) 95-100%
Answer: (C) 90-95%

Q9: What is the purpose of Automatic Voltage Regulation (AVR) in a UPS?
(A) To provide continuous AC power
(B) To maintain a steady output voltage
(C) To prevent overcharging the battery
(D) To protect against power surges
Answer: (B) To maintain a steady output voltage

Advanced Topics

Q10: Which technology is used in modern UPS systems to improve efficiency?
(A) Ferroresonant transformers
(B) Pulse Width Modulation (PWM)
(C) Silicon-controlled rectifiers (SCRs)
(D) Relay-based switching
Answer: (B) Pulse Width Modulation (PWM)