From computers, TV's and stereos to microwave ovens and automatic coffee makers, our homes and offices are filled with devices that were only the dreams of futurists generations ago. Most of these popular modern appliances are controlled by microprocessors -- tiny, delicate silicon chips and circuit boards. These "electronic brains" operate on precise voltages and are more sensitive to variations in utility power supply than appliances from a generation ago.

When there is a power interruption the microprocessors lose their "memory"-- or data. The interruptions are typically so brief ordinary lights will not dim or flicker. In effect, the only thing that "sees" the power variation is the microprocessor.

Eternal Midnight

You may find them annoying, but those digits flashing "12:00" on your VCR, microwave or clock radio -- sometimes called "eternal midnight" -- mean that one of the safety devices installed by your co-op to protect you and your co-op's system has done its job.

The device, named an oil-circuit recloser, acts like a self-resetting circuit breaker. It "opens" and interrupts power for a moment when a short circuit caused by a tree branch, small animal or weather -related problem occurs on the section of line it protects. The recloser waits a short time and "recloses," returning power to the line.

If the short circuit is gone the recloser stays closed and power flows to your home. If the problem persists after three tries, the recloser "locks open" to prevent property damage or personal injury until the problem can be investigated. Reclosers and the switches that route power are essential to the safe delivery of electricity. Unfortunately, they may also cause your clocks to blink.

Minimizing Blinks

It is important to remember that rural electric cooperative power lines are sited through forests, over mountains and across rivers. The lines are constantly exposed to natural conditions that present challenges for providing error free operation.

Steps can be taken to minimize the potential inconvenience caused by a momentary power outage. These steps can be as simple as purchasing appliances -- like clock radios, VCRs and microwaves -- that have a battery back-up system built in. Other electric loads such as computers, printers and facsimile machines can be plugged into an uninterruptible power supply (UPS) system. A UPS system is essentially a plug-in battery back-up and will keep a device running for 15 to 20 minutes during any power interruption. This provides an opportunity to save data before it is lost.

Other Quality Problems

Electrical transients, or spikes, are usually associated with lighting strikes.
Sags are slight decreases in voltage usually caused by start-up of larger equipment, such as a large electric motor in your home or in a business down the road. Swells are slight increases in voltage usually caused by the shut down of larger equipment in your home or in a home or business down the road. Electrical noise, often noticed as static on a radio or a fuzzy picture on television, is caused by appliances with electric motors such as vacuum cleaners, water pumps, power tools and blenders.