DU0-001 · Question #8
How long is the transfer to battery time for a double conversion online UPS?
The correct answer is A. 0 ms (0 cycles). A double conversion online UPS continuously converts incoming AC power to DC and then back to AC through an inverter, meaning the connected load is always powered by the inverter rather than directly from the mains. When utility power fails, the inverter simply draws from the…
Question
Options
- A0 ms (0 cycles)
- B8 ms (0.5 cycles)
- C16 ms (1 cycle)
- D500 ms (30 cycles)
How the community answered
(59 responses)- A83% (49)
- B8% (5)
- C2% (1)
- D7% (4)
Explanation
A double conversion online UPS continuously converts incoming AC power to DC and then back to AC through an inverter, meaning the connected load is always powered by the inverter rather than directly from the mains. When utility power fails, the inverter simply draws from the battery instead of the rectifier, with no switching action required - making the transfer time literally zero milliseconds. Options B and C (8 ms and 16 ms) describe transfer times associated with line-interactive and standby (offline) UPS designs respectively, which must physically switch to battery when a fault is detected. Option D (500 ms) is far too slow for any modern UPS and would cause equipment to lose power entirely.
Memory tip: Think of "double conversion" as the load living permanently on the battery side of the circuit. Since it never leaves that path, there is nothing to transfer.
Topics
Community Discussion
No community discussion yet for this question.