Computer Maintenance · Advanced level

Advanced level · Module 4: Power, Environment and E-Waste · Lesson 1 of 4

Power Problems and UPS Sizing

Choose power protection that matches the load and the outages.

In this lesson you will

  • Recognise power problems
  • Size a UPS for several devices

Key concepts

surges, sags and outagesUPS typesload in wattsrun time

The lesson

Power problems include surges, sags (low voltage) and outages. Line-interactive UPS units handle sags and surges better than basic standby units.

Size a UPS by adding device watts, checking both watt and VA ratings and estimating run time from battery capacity.

Critical equipment such as servers and network devices may need longer run time or a generator.

Step by step

  1. List devices and watts.
  2. Choose UPS type and rating.
  3. Estimate run time.
  4. Plan for longer outages.

Practice activity

Size UPS protection for the case site's key equipment.

Expected result: Justified UPS choices with run-time estimates.

Check your understanding

  1. What is a power sag?

    Show answer

    A temporary drop in voltage.

  2. Which two ratings must a UPS satisfy?

    Show answer

    Watts and VA.

Taught live by an instructor — online or in person. Free course lessons are for self-study and do not lead to a certificate — see registration options.