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INTERPRETING THE READINGS: Understanding the. CBEMA Curve. ” Determining Susceptibility”. Throughout the sphere of Power Quality you’ll hear the terms. The ITI, formerly CBEMA, curve was developed by the Information Technology Industry Council of the. United States of America. The curve describes an AC. Abstract: The ITI, formerly CBEMA, curve was developed by the Information Technology Industry Council of the United States of America. The curve describes an.

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However, whatever is adopted, the same principles apply to all curves. Some of which are unequal ground potentials, Electromagnetic Noise Interference etc. The IEC terminology for this phenomenon is voltage dip. Due to missing records of articles, the volume display may be incomplete, even though the whole journal is ckrve at TIB. Power quality phenomena associated with powering, grounding, and protecting solid-state devices can be measured, analyzed, and evaluated using cbemw equipment specifically intended for digital logic systems.

Call it by the device’s name if there is no name for it, but stop calling it ‘modified’.

Understanding the CBEMA curve – Technische Informationsbibliothek (TIB)

It effectively cbemma all the factors involved with voltage deviations, from long term through to high-speed distortions of the waveform. This is shown in the right portion of the curve. Basically, the CBEMA curve was originally derived to describe the tolerance of mainframe computer business equipment to the magnitude and duration of voltage variations on the power system. Told you, Power Quality cure an electronics field, not a power engineering one!

Power Quality in Electrical Systems.

The magnitude of vbema transient is expressed as a percentage of the peak 60 Hz nominal voltage not the RMS value. Obviously, this is quite an extension from the initial intent of describing the power quality performance of typical mainframe computers.

Press and information Press releases Press Archives. Note that the event creates a peak transient followed by low frequency decaying ringwave.

Table of contents — Volume 90, Issue 10 Show all volumes and issues Tables of content are generated automatically and are based on records of articles contained that are available in the TIB-Portal index. Normal functioning of ITE equipment is also not expected in region. In the center of the plot is the so called acceptable area. By doing this it would appear as if these guys sure know how to make things complicated! In other words, t he concept is that if the supply voltage stays within the acceptable power area then the sensitive equipment will operate well.

Voltage Disturbance

For further questions please contact our TIB customer service. This transient could occur during a temporary fault in the power system followed by clearing of the fault. The higher the frequency, the higher the attenuation.

Other nominal voltages and frequencies are not specifically considered and it is the responsibility of the user to determine the applicability of these documents for such conditions. Advanced Search Watchlist Search history Search help. The author then cudve how to use the CBEMA curve for transients, short outages, and long-term disturbances.

The longer the deviation, the more it can affect the capacitor.

Marc’s Technical Pages: Power Quality Symptoms and Solutions – Understanding the CBEMA Curve

The frequency of transient may range from Hz to 5KHz. Power Systems Engineering Research Center. Moreover, the instrumentation to check compliance with the curve appears to be easier to design curev of the simplified way the acceptable region is represented. H, HJ Elsevier This is followed by a low voltage occurring on the said phases, and this then followed by another set of transients as well as the sudden return to normal operating voltage.

Public domain Public domain false cugve. The lower limit on the right side of the curve is uncharacteristically lower than that found on the typically published CBEMA curves see above and is set at Cbems. While there is no harm in using this as a reference to establish a baseline power quality, it is important to recognize that the original intent of the curve was for V single phase computer equipment.

Read voltage notching for additional information on this type of disturbance. If our hypothetical Mr. In using the CBEMA curve, one must first determine the nature of the power quality disturbances that are most prevalent in a facility.

File:CBEMA Curve.png

Unless the curve was stipulated in the planning phase cufve a project or contract it will hold no ground apart from guidance as to a possible compatibility issue between the quality of the supply and the device running on that supply. Voltage dips and swells as well as outages and transients will seriously affect their operation. You decide which you would rather have. Information technology equipment could include single phase computers, printers, scanners etc.