The need for a UPS

Electrical Power & Protection

July 2000 Electrical Power & Protection

Meisner

Paul Ashworth, Product Manager at local uninterruptible power supply (UPS) manufacturer, Meissner, believes that South Africans are misinformed when it comes to UPSs. "Electrical faults can cripple a company, and the threat is not restricted to a complete power failure," he says

Take the example of a power surge, which occurs when the voltage is 110% of the normal. According to Ashworth the most common cause is heavy electrical equipment being turned off. "Under this condition, computer systems may experience memory loss, data errors, flickering lights and equipment shutoff."

He also warns of a high-voltage spike that takes place following a sudden, rapid voltage peak of up to 6000 V, often caused by nearby lightning strikes although there may be other causes as well. In these circumstances vulnerable electronic systems may experience data loss and burned out circuit boards.

Transients commonly stemming from arcing faults and static discharges, or major power system switching disturbances - initiated by the utilities to correct line problems may happen several times a day. Effects can include memory loss, data error and component stress.

"Power sags, where line voltage can fall as low as 80 to 85% of normal for a short period of time - possible causes include the starting of heavy equipment or large electric motors, and the switching of power mains (internal or utility)." explains Ashworth. "These can cause memory loss, data errors, flickering lights and equipment shutoff."

A frequency variation involves a change in frequency from the normally stable utility frequency of 50 or 60 Hz, depending on the geographic location. This may be caused by erratic operation of emergency generators or unstable frequency power sources. For sensitive electronic equipment, the result can be data corruption, hard drive crashes, keyboard lockups and program failure.

Lastly, Ashworth warns that people should be careful of a brownout. "It is a steady lower voltage state which usually happens during peak electrical demands in the summer, when utilities can't always meet the requirements and must lower the voltage to limit maximum power." When this happens, computer systems can experience data corruption, data loss and permanent, premature hardware failure.

To ensure comprehensive protection of assets, users will be wise to consider obtaining a UPS. "These threats are real and could cause serious damage, the only sure way to prevent loss of data or memory is by installing a UPS unit," concludes Ashworth.

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Electrical Power & Protection

The need for a UPS

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