CHOOSING A UPS

What does a UPS do?

Uninterruptible Power Supplies (UPS) are designed to provide an alternative source of power to electrical equipment in the event of an irregularity or failure of the mains power feeding the equipment. The input power requirements and the task of the equipment concerned will largely determine what type of UPS protection is needed.

How many types of UPS are there?

In general terms:

• Off line uninterruptible power supplies (UPS) monitor the power supply and provide temporary battery power if the quality of the supply moves outside an acceptable level, or if there is a power cut.
• Line interactive uninterruptible power supplies (UPS) correct power inequalities within a suppression range as well as providing temporary battery back-up if power fails.
• Online uninterruptible power supplies (UPS) condition and regenerate the power supply at all times, correcting all irregularities, including enabling longer-term battery power if the supply fails. On-line uninterruptible power supplies (UPS) are very reliable and are amongst the most advanced UPS’s available.

When choosing a UPS the first consideration must be to decide the level of protection that will be required.

How is the right size of UPS selected?

Typically, an uninterrupted power supply (UPS) has a VA rating and there are two quick ways in which the necessary VA rating can be assessed. If the power demand of the equipment to be protected is expressed in Watts, the VA rating of the required UPS can be calculated by dividing the number of Watts by 0.7.

Alternatively, the VA rating of the required UPS can be calculated by multiplying the power input requirement of the equipment expressed in amps by 230. The amps input is shown on the equipment’s CE Mark plate.

How long does a battery last?

Battery autonomy or back up run times of approximately 10 minutes are typical of most user requirements, however in some applications, such as telephone switch boards, longer run times are often required. These longer run times can be achieved by adding additional battery cabinets to the existing battery sets inside the UPS.

UPS battery testing is critical to ensure the UPS battery is functioning correctly. A battery will generally start to get tired after three or four years of normal use. Heavy usage, or failure to fully charge a battery at least three or four times a year, can shorten battery life. UPS battery testing should be undertaken at least every 2 years.

With a UPS, the user is able to remove the threat posed for sensitive electrical equipment by unreliable power quality. If you still have questions about UPS please contact us.