NETA Battery and UPS Systems Testing 2

Question 1

Which UPS topology provides zero transfer time to battery during a utility power outage because the load is always powered by the inverter?

Accepted Answer

Double-conversion (online) UPS

Answer

Standby (offline) UPS

Answer

Line-interactive UPS

Answer

Delta-conversion UPS

Question 2

During a UPS acceptance test, which specific test verifies that the inverter can independently support the full connected load without utility input?

Accepted Answer

Battery runtime (discharge) test

Answer

Static bypass transfer test

Answer

Transformer turns ratio test

Answer

Output THD measurement

Question 3

What output power quality parameter should be measured at the UPS output terminals during load acceptance testing to assess the quality of power delivered to critical loads?

Accepted Answer

Output voltage regulation and total harmonic distortion (THD)

Answer

Battery specific gravity

Answer

Charger ripple current

Answer

Rectifier input current

Question 4

When the static bypass switch in a UPS system transfers the load, where does the load power come from?

Accepted Answer

Utility (bypass) power, bypassing the rectifier and inverter

Answer

The battery bank directly

Answer

The inverter operating in boost mode

Answer

A motor-generator set

Question 5

Failure of which component in the UPS rectifier/charger section would most likely cause excessive AC ripple voltage on the DC bus?

Accepted Answer

DC filter capacitors

Answer

Static bypass switch

Answer

Output isolation transformer

Answer

Battery monitoring board

Question 6

What is the purpose of applying an equalization charge to a flooded lead-acid battery string?

Accepted Answer

To apply a controlled overcharge that equalizes cell voltages and specific gravity across all cells

Answer

To reduce the battery to 80% state of charge for capacity testing

Answer

To measure each cell's internal resistance under load

Answer

To verify proper calibration of the battery charger's output

Question 7

During UPS output testing, what does proper automatic voltage regulation (AVR) function demonstrate?

Accepted Answer

Output voltage remains within specification despite input voltage variations

Answer

The inverter switches to bypass within 4 milliseconds

Answer

Battery charging current remains constant during input fluctuations

Answer

THD decreases when input voltage rises above nominal