First decide what equipment you want to use the UPS for. At a minimum it should be your computer and perhaps one terminal. By having a terminal on the UPS this will allow you to shutdown the computer before the UPS runs out of juice.

On the back of the equipment there should be a listing in either watts or amps. You need to calculate the voltage-amps (VA) power rating. If watts is given, VA=watts x 1.7. If amps is given, VA=amps x 120. Add up the total VA values. You will need an UPS with at least the total VA value.

It is recommended to go higher than your VA total. A VA of 600 on a UPS rated at 600 will run for about 5 minutes. By increasing the UPS to 900, the same VA of 600 will increase the run time to 15 minutes.

These simple instructions will allow you to verify the battery power of your UPS. Over time, UPS batteries wear out. This leads to a loss of power capacity and runtime. Testing your unit monthly will ensure that the batteries are still providing the required runtime for your system.

Depending upon the model of UPS you own, you may either perform a manual test on your unit or use APC's PowerChute(R) plus software to monitor and log the results of the automatic battery test.

To perform a manual test you..

• Simply press the test button located on the UPS.
• After testing, if you find that the battery indicator has turned red, then you may need to replace your batteries or upgrade your UPS.

The new APC systems have user-replaceable batteries which can be changed with no system downtime! If your UPS has neither a self-test button nor PowerChute, you have a very old model. It's probably time to upgrade your UPS.

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Blackout

This is when the power drops to practically or absolutely nothing. In a study by IBM of the five major causes of power disturbances, blackouts rated for only 1% of the total. UPS are the only devices that will handle blackouts.

Brownout

This is a temporary reduction in power which can last from seconds to hours. This is the most significant of power problems and accounts for 87%. Utility companies will sometimes actually cause a brownout on purpose to provide a little power to everyone during high demands. Conditioners or an UPS with conditioner will handle brownouts.

Surges

A surge is a transient increase of power for more than a fraction of a second and less than 2.5 seconds. Surges cause a power supply to generate heat. Heat is the major cause of equipment failure. SURGE SUPPRESSORS DO NOT SUPPRESS SURGES, they only suppress spikes. Conditioners or an UPS with conditioner will handle surges.

Spikes

Spikes are an intense increase/decrease in voltage. They are more extreme than a surge and of shorter duration. Spikes can mess up the computer's memory causing weird or strange things to happen. In extreme cases, spikes can actually melt wiring. An IBM study predicts a power disturbance at least twice a day. Surge suppressor protect against spikes. Don't ask why they don't call them spike suppressor.

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Surge Suppressor

There are three types of suppressor.

• Metal-oxide (MOV) based. They become less effective with each surge. Not very durable to offer reliable protection.
• Silicon avalanche diodes. Do not degrade.
• MOV or silicon based combined with a "gas tube". They can handle large amounts of energy. Suppressor should have rating of IEEE 587 or UL 1449.

UPS

These also come in three types.

• An online UPS continuously draws current from power line and the computer gets all of its power from the UPS. At one time these were the most reliable because there is only an instant between the time power drops and the UPS kicks in. Most important in hospital life support systems.
• Off-line or standby waits for a problem and kicks in when the power fails. The benefit is that the batteries don't wear out as soon as onlines. Current off-line models kick in just as quick as online models.
• Line interactive is a hybrid of online/offline. The computer draws very little power from the UPS unless the power drops. Average battery life is five years.

Line Voltage Regulators

These protect against voltage fluctuation but don't handle surges, spikes or blackouts.

Isolation Transformers

These protect equipment from electrical noise. They are used with mainly communication and process control equipment.

Power Line Conditioner

This is a combination of line voltage regulator, isolation transfer and surge suppressor. It handles everything but blackouts.

Telephone Line Surge Suppressor

This is a type of surge suppressor. Because a modem provides little or no power protection, power problems over phone lines can be more destructive than over electrical power lines.

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