Uninterruptible Power Supplies

Shop uninterruptible power supplies used to provide temporary battery-backed power and help protect industrial, commercial and electronic equipment during power interruptions and selected voltage disturbances. Available designs may include AC UPS systems, DC UPS systems, DIN-rail UPS systems and online UPS systems.

Compare UPS systems by input and output voltage, power capacity, topology, battery runtime, mounting method and communication features. The UPS must be sized for the connected load, required runtime and any temporary startup or inrush demand.

How to Select an Uninterruptible Power Supply

An uninterruptible power supply provides temporary electrical power when the normal source is interrupted. Depending on the UPS design, it may also help address voltage fluctuations, electrical noise and other power-quality conditions before they reach connected equipment.

UPS selection should begin with an accurate inventory of every connected load. The system must support the combined steady-state demand, temporary startup current and the amount of runtime needed to maintain operation or complete an orderly shutdown.

Common UPS Types

• Standby or offline UPS: Transfers the connected load to battery-backed output when normal power falls outside the acceptable range.
• Line-interactive UPS: Provides battery backup and may correct selected voltage variations without using the battery continuously.
• Online UPS: Continuously converts incoming power and supplies the load through the inverter for applications requiring a high level of power conditioning.
• AC UPS systems: Supply conventional AC-powered equipment during an interruption.
• DC UPS systems: Support DC control equipment and may integrate with industrial power supplies, batteries and battery-management modules.

Important Selection Factors

• Input and output voltage: Match the available source and connected equipment.
• Load capacity: Compare both watt and VA requirements where applicable.
• Required runtime: Determine how long the load must remain powered after an interruption.
• UPS topology: Select standby, line-interactive or online operation according to the application.
• Startup demand: Account for temporary inrush from motors, transformers and other loads.
• Battery configuration: Review internal batteries, external battery cabinets and replacement-battery requirements.
• Mounting method: Choose DIN-rail, rack, tower, panel or floor mounting as required.
• Communications: Determine whether network, USB, relay-contact or remote-monitoring functions are needed.
• Environment: Verify operating temperature, enclosure, ventilation and applicable approvals.

Replacement Checklist

• Manufacturer and complete UPS model number
• Input and output voltage
• Connected load in watts and VA
• Required battery runtime
• AC or DC output requirements
• Mounting and dimensional requirements
• Communication and monitoring requirements
• Existing battery or external battery-cabinet information