How Do I Know If My Uninterrupted Power Supply Is Working?

Devices plugged into an uninterruptible power supply won't shut down unexpectedly from a power outage or low voltage.

An uninterruptible power supply (UPS) can be vital for computer users when an unexpected loss of electrical power occurs by providing battery power for a brief period to provide the user time to save programs and shut down the computer properly.

Function

An uninterruptible power supply uses electricity to charge an internal battery while also acting as a power adapter to direct the correct voltage to the computer or other device connected to it. The uninterruptible power supply monitors the electricity coming from the electrical outlet it is plugged into and automatically switches to battery power output when the electrical load fails or drops below the required voltage to power the device plugged into the UPS.

Types

A standby uninterruptible power supply is equipped with a transfer switch that switches power output from the electrical outlet to the battery with a lag time of approximately two milliseconds to 10 milliseconds. Line interactive UPS devices use a portion of the electrical power to keep the battery charged and switches to battery power when the electrical current fails. An online uninterruptible power supply constantly delivers some or all of its power output through a battery-powered inverter.

Testing

Many UPS units have status lights to indicate if they are ready to react to a sudden loss of power. If your UPS doesn't give such an indication, you can test it by plugging in and starting up your computer and, after allowing time for the battery of the UPS to charge, cutting power to the outlet or unplugging the UPS.

References

• Uninterruptible Power Supply (UPS):Buying Guide
• B.C. Hydro:Uninterruptible Power Supply:Specifications and Installation Guide