Power problems can be baffling.
Where do they come from? What causes them? Can you do anything about the problems that are affecting your system? Though there are all kinds of equipment available to help eliminate many power disturbances, how do you know what is right for your particular situation? Maybe you have purchased line conditioning equipment already, and are still having problems. Can you specifically identify what is wrong so you can go about fixing it? If you are planning a move to another location, or installing a new system, can you be sure that the electrical plant is stable and ready?

Electronic equipment requires clean, stable power. At Rountree & Associates, we have the solutions you need! We want you to know how to fight power problems and avoid lost data. We can help you diagnose your power problems and help you protect your electronic investments. Best of all, it's inexpensive and as easy to use as plugging in a clock radio!

We have developed an easy to use method of analyzing your electrical system over time, and providing you detailed information about the power events that occur in your office. Armed with real  information about what is actually happening with your power, you are in a far better position to get to the source of the problem and eliminate it. 

What is the solution, and how does it work?
Our system consists of a small box that is shipped to your door when you order an analysis. We can ship to anywhere in the world, and analyze most kinds of electrical power systems. You simply plug the box into the circuit you want to test, and it immediately begins analyzing your power and recording the events that occur. You also receive a number of printed forms for your use in coordinating simple tests like turning on and off the air conditioner, copy machine, and other devices you may have in your office, and recording the date and time you tested each. Then, just go about your normal business day, and let the system work for you! After you have monitored your power for whatever time you feel is adequate for your needs, usually a week or two, we call for a pick-up and collect the box along with your forms. When we receive the box in our lab, we extract and analyze the data, print reports and graphs to describe to you how stable your power source is, and send you the information in whatever form is most convenient for you. 

Here's what you get:
 
A complete "snap shot" of your power problems over a designated time period. 
A printed report that describes your power problems, when they occur, the types of problems, and the equipment that may be causing them.
A software package that installs on your computer complete with the data from your analysis. 
You can print your own reports using different sort orders to find trends, export the data to a spreadsheet for charts, graphs, or computations.
Temporary space on our website for your company to login to which displays your analysis so you can coordinate branch offices.
Upon your request, we will help you to choose equipment to help solve the problem. 

All at a fraction of the cost of expensive chart recording equipment rentals!
Additionally, we can give you advice on how to coordinate a plan if your problems  involve your local power utility or electricians. If you already have equipment, and need to verify it's capacity to stabilize your power, you can arrange for an "input/output" comparison analysis of raw voltage compared to the voltage coming out of your conditioning equipment.

Contact us for more information, or to request an analysis!
Types of Power Problems
There are many types of power problems that can affect the quality of the AC power being delivered to a piece of equipment. Different types of problems will have different effects on the operation, or even life expectancy of this equipment. Knowing what these problems are, and what some of the consequences are of having these problems, can help in the process of identifying what can be done to help protect this equipment. The following pages describe several of the more common types of Power disturbances, and list what some of the causes are.
  • SAG (UNDER-VOLTAGE, DIP, or BROWNOUT)
  • SURGE (SWELL OR OVER-VOLTAGE)

DROPOUT (NOTCH)

A condition where a portion of the sine wave has a lower than expected value or is missing entirely, usually for a portion of a cycle. These types of problems can be caused when large motors are started, Lightning arresters are employed (during a lightning hit), or when electrical equipment fails. Dropouts can lead to failures in computers and electronic equipment , reduced life of motors and flickering lights.

POWER FAILURE

When the duration of a dropout exceeds 1 cycle it is usually referred to as a Power Failure, or Blackout. This problem is usually the easiest to observe

SAG (UNDER-VOLTAGE, DIP, or BROWNOUT)

A power sag (or low line voltage) is a decrease in line voltage of at least 10% of the average line voltage for half a cycle or longer. The power sag is often caused by large inductive equipment (e.g. photocopy, postage equipment) being applied on the same AC line as is being tested. Sags can be caused by external factors as well, such as large power draining equipment used in other buildings. Sags can be particularly detrimental to electronic equipment because of the malfunctions caused by the sudden decrease of available voltage to the power supply. Complete failure rarely occurs, and often the equipment user continues to operate the device, unaware of the potential logic circuit problems that may have occurred.

HIGH FREQUENCY NOISE

High frequency noise can be caused by electronic equipment feeding internal noise back onto the power line, or logic induced noise from switching power supplies. This noise is transferred to the AC line causing disturbances greater than 2V peak-to-peak superimposed on the AC sine wave (normal mode noise). This noise can cause internal component degradation and eventual system failure. During this degradation period, system lockups, resets and data transfer will increase.

SURGE (SWELL OR OVER-VOLTAGE)

A power surge is the opposite of a sag and is often referred to as "High Line Voltage". A surge is defined as an increase in line voltage above 128 volts (on a 115V Line) for a half cycle or longer. Like the sag, the power surge is often caused by large inductive loads being applied on the same line. Power surges cause some of the most dangerous occurrences, and their results are the most difficult to correct. 

COMMON MODE NOISE

In single phase power systems, as found in many countries such as the USA, the load (computer or equipment) is connected between the hot and neutral line. Usually the neutral line is connected to earth ground at the service entrance, so that in effect the neutral line should have 0 volts at the load. At a typical site, voltage is induced onto the neutral line by other equipment. This voltage can appear in the form of impulses, or a continuous pseudo sine wave.

IMPULSE (SPIKE, SURGE)

The spike is a surge of energy superimposed on the AC line, usually with a relatively short duration. Spikes can potentially have the most serious effects on electronic equipment due to their high energy content, and the Integrated Circuits inability to absorb the energy. Many events can cause spikes, such as lightning bolts, utility grid switching, switching inductive loads on and off, and SCR (Silicon Control Rectifier) dimmers. Although properly designed equipment has some built-in spike protection, repeated hits by high energy spikes can eventually render these components useless.		 Types of Power Protection Equipment
The following is a brief overview of several different types of power protection devices.

SWITCHING POWER SUPPLIES

The most basic defense against power disturbances is located right in the power supplies of most electronic equipment. These power supplies act as filters, "cleaning" the incoming AC and sending it to the components as DC power. Even though these power supplies can remedy many of the small AC disturbances and protect your equipment to a small degree, they cannot begin to filter everything the AC line has to offer. Repeated hits of spikes and noise will break down the efficiency of the minimal built-in power protection.

SPIKE AND SURGE PROTECTORS

By far the least expensive type of power protection, spike and surge protectors (or "clippers") act by cutting off voltage when it exceeds a certain level and sending this offending voltage away from the sensitive circuits of electronic equipment. This excess voltage is sent to devices called Metal- Oxide Varistors (MOVs) which take the voltage and convert it to heat which dissipates over time. Whereas these surge protectors are good for short-term use, and they are inexpensive (usually under $50), the MOVs inside them degrade after a relatively short time due to repeated heating and cooling. Also, these protectors will function as long as the voltage does not exceed the specifications of the components inside. There are basically two types of spike and surge protectors: tracking and non- tracking. The difference between the two is that the tracking device will "clip" a spike to a certain limit anywhere on the sine wave whereas the non-tracking protector will clip a spike only when its magnitude reaches the clamping level, regardless of its position on the AC waveform. The tracking surge protector is the more expensive of the two.

POWER LINE FILTERS

Power line filters are designed to suppress spikes, surges, and noise before they get to the clipping level of common surge protectors. Instead of clamping the voltage when it exceeds the cutoff, the power line filter limits noise and spikes to a safe level by slowing down the rate of change of these problems, thereby keeping electronic systems safer than the surge protectors can. Of course, these filters are more expansive and range upwards of $200.

COMPUTER GRADE TRANSFORMERS

These power protecting devices are multiple shielded transformers whose job it is to suppress spikes and common mode noise. Although this seems much like power line filters, they are different in that they isolate primary and secondary AC, thereby establishing a safe and reliable ground for the electronic device it is protecting. Computer grade transformers are ideal for use when grounding is a problem because of an industrial environment.

LINE VOLTAGE REGULATORS

Voltage regulators maintain voltage to within a very narrow tolerance regardless how much the AC line varies in terms of voltage. While these regulators offer some surge protection, they do not provide good isolation like computer grade transformers.

POWER LINE CONDITIONERS

These are excellent power protection devices as they are essentially a combination of computer grade transformers and line voltage regulators. They provide spike, sag, surge, and noise suppression while isolating the AC lines and providing an excellent system grounding point.

UNINTERRUPTIBLE POWER SUPPLIES (UPS)

These are the most complete power protection devices available. They operate by providing continuous, uninterrupted AC power from an isolated, regulated source regardless of the quality of the primary AC line. These power supplies are constantly supplying the system with clean AC power. Small UPSs contain built-in batteries which supply the system with DC power when a complete power failure occurs. Larger units use an external battery allowing for orderly shutdown of all systems during a power failure, or for activating backup generators. All UPSs provide very significant protection against all power problems, the better models approaching absolute protection.

STANDBY POWER SUPPLIES (SPS)

These units differ from Uninterruptible Power Supplies in that the AC power is connected through a power line filter to the computer system. The SPS only begins to supply the computer with clean AC power when it senses a voltage interruption. At this time it activates an outside AC source and transfers its output to it. These SPSs are less expensive than UPSs, however, for most small systems they can be used in place of a UPS and still gain the same benefits. The reason for this is that it takes only a few milliseconds for an SPS to switch to the alternate AC source, and most small systems do not notice this short gap without power.

APC, Best, Exide, Liebert and Tripplite are some of the manufacturers of these types of power protection equipment.