A UPS can provide battery-backed power and power conditioning, but choosing the right system requires more than selecting a VA rating.
Why use a UPS?
IT equipment depends on stable electrical power. A UPS can help provide continuity during power interruptions and can provide power protection appropriate to the UPS design.
Line-interactive UPS
Line-interactive systems are commonly used for business and equipment-room applications where a combination of battery backup and power regulation is required.
Online UPS
Online double-conversion UPS systems use a different power architecture and are intended for applications where a higher level of power conditioning and continuous protection is required.
Long-life UPS systems
Where longer runtime is required, the battery configuration and load need to be considered together. Runtime is affected by the connected load and the UPS and battery design.
Calculate the load first
Start by listing the equipment that needs protection. Servers, storage, network switches and other equipment can have different power requirements. The UPS should be selected against the actual and expected load rather than the equipment count alone.
Runtime is a separate decision
Two UPS systems with similar power ratings can have different runtime characteristics. Decide how long the equipment needs to remain powered during an outage and what should happen when the available battery runtime is reached.
UPS selection checklist
- What is the actual connected load?
- What capacity is required?
- How much runtime is required?
- Is line-interactive or online technology appropriate?
- What equipment needs battery-backed power?
- Is network monitoring or management required?
- What battery replacement considerations apply?
- Is future load growth expected?