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Exin CDCS Exam - Topic 1 Question 29 Discussion

Actual exam question for Exin's CDCS exam

Question #: 29
Topic #: 1

[All CDCS Questions]

Which class of UPS is ideal for data centers?

AVFD (Voltage and Frequency Dependent)

BVI (Voltage Independent)

CVFI (Voltage and Frequency Independent)

DFirst class

Show Suggested Answer

Suggested Answer: C

IEC 62040 defines UPS topologies:

VFD: Line-interactive; dependent on mains.

VI: Stabilizes voltage but not frequency.

VFI: Double-conversion online; fully isolates output from mains fluctuations.

Data centers require continuous, clean, and stable power. VFI is the only topology that protects against both voltage and frequency disturbances, meeting ANSI/TIA-942 Rated-3/4 requirements.

Thus, VFI is the ideal UPS class.

by Sanda at May 12, 2026, 08:35 AM

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Stephaine

1 month ago

I think the VFI class is the best choice for data centers, but I’m not entirely sure why it’s preferred over the others.

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