At first glance, specifying an uninterruptible power supply seems a complex task. But in essence, whether you’re buying a new UPS system or replacing an existing unit, the choice boils down to two main factors: required load and battery autonomy.
To establish the required power consumption, separate out the critical loads (that will need protecting by the UPS) from the non-critical. In a call centre, for example, telephones and computers would be classified as critical, but desk fans not. For a factory, production lines and machinery are critical, but non-essential lighting or telephone lines not so much.
Establishing the load requirement will determine which UPS topology is best-suited (standby/offline, line-interactive, or online).
The second main criteria is battery autonomy. How much runtime do you need to carry out a safe shutdown? When you’re thinking about runtime, you should also consider how much space you have to install batteries.
Other Factors Influencing Your Choice Of UPS
- Installation environment: do you need a freestanding tower (typically for industrial sites) or rack-mounted (usually with IT loads) UPS? And where will the UPS be fitted? UPS systems work best in dry, dust-free, well-ventilated rooms with a consistent and controlled temperature. If the UPS is rear rather than front-venting, you’ll need to leave a 300mm gap.
- Installation configuration: do you need to build in redundancy, such as an N+1 parallel system, to mitigate against the risk of serious system failure?
- UPS maintenance: does the UPS have front panel access for maintenance or does it require side access? If it’s the latter, it has implications for configuring the system.
- Warranties: the industry norm for UPS systems is a two or perhaps three year warranty. Riello UPS offers a five-year extended warranty as standard on all UPS up to and including 3 kVA.
- Accessories: It’s recommended to always incorporate a bypass switch. Depending on your networking and communications requirements, SNMP cards or other BMS connections might be advisable.
- Features: does the UPS include an LCD or even touchscreen display panel that gives you important performance information? What operating modes does it have (i.e. ECO mode, Smart Active, Frequency Converter)?
Specifying the correct UPS system often requires a site survey.
Watch our ‘UPS Basics’ video to get more advice on how to choose the best UPS system.