Technische Bibliothek

Technische Bibliothek

In unserer Fachbibliothek bieten wir Ihnen eine große Auswahl an technischen Leitfäden und Abhandlungen zu unseren Produkten im Speziellen und im Allgemeinen - sowohl in englischer und deutscher Sprache. Mit dem praktischen Filter können Sie unseren Bestand durchsuchen oder Ihre Suche für bestimmte Anwendungsbereiche verfeinern. Bitte beachten Sie, dass Sie ein Konto erstellen müssen, um auf unsere Ressourcen zu greifen zu können.

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    Artikel anzeigen 31 - 40 von 302 insgesamt
Transformer turns ratio test: some unknown facts
Transformer Turns Ratio (TTR) is one of the most common test used to assess the condition of the transformer’s windings and core.  It is performed as a part of acceptance and maintenance test procedure to determine any problems due to poor design, assembly, handling, overloading, fault conditions or poor maintenance. TTR results are compared against the nameplate ratings to determine any possible insulation deterioration, shorted turns, core heating or any other winding or core abnormalities.TTR is a simple and easy test to perform that is often taken for granted without fully understanding the principle and basis of the test. In cases when measurements are not within expected limits, it becomes a challenging task to determine the root cause and resolve the problem. This paper will focus on some of the unknown facts associated with the TTR test. The paper covers in detail the effect of applied test voltage, comparative analysis of step up vs step down excitation, different vector configurations, differences between nameplate ratio, voltage ratio and turns ratio, sources of ratio and phase angle errors, comparison of per phase testing vs true three phase testing, extreme tap ratios being out of tolerance for On Load Tap Changers (OLTC), and TTR test correlation with other electrical tests. The paper also provides field test results and case examples to explain the above-mentioned unknown facts.
Veröffentlicht: 28 April 2020
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Megger PQ PC Software für MPQ Serien PQ Analysatoren
Herunterladen des Installationpakets um die neue MPQ Software auf Ihren Computer zu laden.
Veröffentlicht: 23 April 2020
One touch OLTC with the TTRU3
Completing turns ratio tests on all transformer taps can be a cumbersome process. With One Touch OLTC from the TTRU3, anyone can configure and test all taps within a few short minutes.
Veröffentlicht: 22 April 2020
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Rapid Voltage Change (RVC)
A rapid voltage change is a fast rise or fall of the RMS voltage. This can be caused by the switching on of a specific load or by a sudden change in source voltage. Sudden source voltage changes can occur in solar grids when the sun is obscured by clouds. Source voltage changes can also occur in wind farms when then wind speed decreases. Load switching can cause a rapid voltage change if the rating of the load is a significant fraction of the fault level of the supply voltage.
Veröffentlicht: 30 März 2020
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Pumping Station Motor Analysis
This test was performed at a pumping station that was using multiple 600HP motors and a VFD drive. The reported problem was the plant was not receiving adequate power output from the motors during peak times. It was not possible to connect to the inputs of the motors themselves so an MPQ2000 was connected to the output of the VFD and the following measurements were recorded.
Veröffentlicht: 30 März 2020
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Pre-location based on impulse reflection methods
The use of T-branches in low voltage networks makes the evaluation of TDR traces considerably more difficult. Only through comparative measurements of fault-free and defective wires can possible results be achieved. The test pulses of the Teleflex are partially reflected at the T-joint with a negative algebraic sign, while test pulses that continue are simultaneously reduced in amplitude. The amount of reflection depends on the impedance in the main line and the continuing line.
Veröffentlicht: 30 März 2020
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Overview of low voltage test methods
Overview of low voltage cable fault location test methods
Veröffentlicht: 30 März 2020
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MPQ1000 Common Connections
An application note locoking at the common connections of the MPQ1000.
Veröffentlicht: 30 März 2020
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Methods of fault location in low voltage networks
There are multiple ways to find a cable fault in a low voltage network, but no one method works for all situations. It’s only by knowing the pros and cons of each method that you can determine the most effective one to use in any given scenario and pinpoint the fault in as little time as possible.
Veröffentlicht: 30 März 2020
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Merging MPQ Data Files
Adding, removing or changing a piece of equipment in a facility can have significant impacts on the power quality and energy requirements. Introduced power quality phenomenon can cause equipment to trip off line. This can represent significant losses in revenue. Added equipment can create high peak loads or increased reactive currents that can lead to penalties. In order to determine the impact of these changes a power quality and demand study should be performed prior to the change and after the change.
Veröffentlicht: 30 März 2020
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  • Artikel anzeigen 31 - 40 von 302 insgesamt