Which UPS topology uses a transfer switch between the primary power source and the inverter?

Question

Options

• AStandby
• BHigh-speed relay
• CDelta conversion online
• DDouble conversion online

• A
  85% (23)
• B
  4% (1)
• C
  7% (2)
• D
  4% (1)

Explanation

A Standby UPS keeps the load running on utility (primary) power during normal operation and uses a transfer switch to redirect the load to the inverter only when utility power fails or falls outside acceptable parameters. This topology is defined by that transfer switch acting as the gatekeeper between the two power paths. High-speed relay is not a recognized UPS topology category - it describes a switching mechanism, not an architecture, and may be a distractor designed to sound like a technical variant of standby switching. Delta conversion online uses a delta converter to supplement power quality in series with the load, and the inverter shares the load continuously rather than being held in reserve behind a transfer switch. Double conversion online routes all power through a rectifier and then an inverter continuously, so the load never runs on raw utility power and there is no transfer switch in the primary power path (only a static bypass for maintenance).

Memory tip: Think "Standby = standing by on the sidelines." The inverter waits behind the transfer switch until it's called in, just like a substitute player waiting on the bench.

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