Care & Maintenance Ideas for Friendlier Electronic Equipment - Part II

By: F. J. STIFTER
PRESIDENT, ELECTRONIC SPECIALISTS, INC.
http://www.elect-spec.com

Last time we discussed 2 of the major surge/spike/interference sources. This time we'll try to figure out - Who to Blame?

Is the Power Company at Fault ??

Electrical power companies around the country strive hard to generate clean, steady, dependable electricity. By the time this new, shiny electricity gets delivered to electronic equipment across the land, this electrical power has become polluted with spikes and surges and all manner of interference.

Not Healthy.

How did this happen?

Thousands of external spike, surge and interference sources act upon AC Power before it reaches your delicate equipment. Industrial machinery, office equipment, traffic lights, household appliances, radio & TV stations and Mother Nature are only a few of many factors, which contribute to AC electric power corruption and pollution.

Horrors! Even components within the immediate equipment configuration may contribute spikes and interference, leading to damage and disruption. Much like kids bringing a cold home from school.

Heavy duty machinery or controlled devices may not be electrically isolated from controllers or computer.

Large laser printers or computer controlled tools may also require electrical isolation from the controller.

Well, maybe we can blame Mother Nature !

Lightning and other natural events often induce severe spikes, surges and interference on power lines, phone lines, network and video cables.. Lightning, more common and severe in summer, is a major cause for concern year round.

Broadly speaking, lightning is an electrical arc discharge between a charged cloud and earth; or between two oppositely charged clouds. A visible arc or ‘‘bolt’’ is created by the discharge current path. Discharge current continues between these two oppositely charged points until sufficient voltage equilibrium is reached so current can no longer maintain the arc.

Engineering studies show that it requires several million volts to initiate the lightning ‘‘bolt’’ or arc.

Studies also show that ‘‘bolt’’ or arc current may reach several million amps.

Over a billion horse-power in that Lightning Bolt!

Impressive, eh?

As this massive ‘‘bolt’’ or arc current begins to flow, a gigantic magnetic field is created. This large magnetic field spreads out from the ‘‘bolt’’ and sweeps across the country side, cutting across everything in its path.

Commercial electricity is generated by passing a wire loop through a magnetic field in the power company generating station alternators. (Actually many loops, dynamo driven through a very strong magnetic field)

Similarly, electricity is generated in wires that are swept by this gigantic, lightning caused magnetic field.

Electrical power lines, telephone lines, coaxial network and video lines (even metal clothes line !) have large voltage spikes and surges (up to 6,000 volts!) and interference inductively coupled by this sweeping magnetic field. These spikes, surges and interference are applied to all line connected equipment.

After the ‘‘bolt’’ or arc is extinguished, the built up magnetic field collapses, inducing another series of spikes, surges and interference.

From the preceding discussion, it’s obvious power, phone, data, video or network lines need not suffer direct lightning hits to develop damaging high voltage spikes, surges and interference.

Other natural events, such as spherics from wind, dust or snow storms also induce severe interference, surges and transient spikes on lines and cables. Although results from spherics can damage equipment and disrupt operation, they are seldom as severe as lightning.

And what about Man? (always a good fall guy)

Man Made Problems - Industrial machinery, electric motors, air conditioners, relays, power company switch gear and other heavy duty power equipment create high voltage surges, spikes and interference year round.

Even a simple home vacuum cleaner or refrigerator may create these problems. Surges and spikes from these sources can reach 2,000 volts and often inflict serious damage to Industrial controllers, computers and measurement equipment.

Of course, connected phone, data or network lines are liable to pick up power line induced transients, surges and interference.

Many experts feel delicate Industrial electronic equipment is more at risk from AC Power Line surges, spikes and interference than from lightning.

Side Effects

Bear in mind that not all AC Power, data, network, video or phone line spikes/surges are severe enough to cause immediate equipment damage. Delicate circuits can be over stressed. Each over voltage hit degrades circuits and components a bit more; becoming more prone to interference or damage. After a number of hits, failure finally results.

A couple of severe storms could degrade the equipment, with actual system breakdown occurring much later when a shop vacuum cleaner was switched on!

High performance protective systems, as discussed in the next sections, clamp power, phone, video and data line surges and spikes to safe limits, holding over-stress to a minimum level, prolonging equipment life. Filtering systems are presented that remove disruptive interference.

Next Time

Our next tutorial installment will discuss - What can be done?

<<< Back To Part 1     To Part 3 >>>

About the Author:

F. J. Stifter is the president of Electronic Specialists Inc., a company that was founded in 1971 to develop and market protectors and interference control products for High Tech equipment. Electronic Specialists develop an extensive array of high tech equipment enhancement products, with primary focus on high performance systems requiring high level interference filtering and total spike surge suppression.