Testing instrument transformers

Conformance test procedure for instrument transformers (CTs and electromagnetic VTs)... 

Witte, R.A. 1993. Spectrum and Network Measurements. Prentice-Hall, Englewood Cliffs, Nf Witte, R.A. 1993. Electronic Test Instruments Theory and Applications. Prentice-HaU, Englewood Cliffs, NJ. For further investigation of the history of Fourier and his transform, the following source should prove interesting ... 

Before the widespread availability of instrumental methods the major approach to structure determination relied on a battery of chemical reactions and tests The response of an unknown substance to various reagents and procedures provided a body of data from which the structure could be deduced Some of these procedures are still used to supple ment the information obtained by instrumental methods To better understand the scope and limitations of these tests a brief survey of the chemical reactions of carbohydrates is m order In many cases these reactions are simply applications of chemistry you have already learned Certain of the transformations however are unique to carbohydrates... 

J) Source side resistance R (to control the p.f. as per the test requirements) High current step down transformer Test object (j Current shunt (2) R-C voltage dividers (12) Recording instruments ... 

Polarity test to check the connections through the potential transformer to ensure that the connections between the transformer and the meters or relays have a correct relative polarity. Otherwise the meters would show erratic readings, while the relays would transmit wrong signals. This test may also be conducted with a low-voltage source of 10 V by ob.serving the deflection of the instruments. 

The AFEX reactor consisted of a 300 ml stainless steel pressure vessel (Parr Instrument, Moline, IL) (Fig. 3). The vessel was loaded with prewetted transgenic tobacco leaves with the desired moisture content (a range of moisture content was tested to determine the effect of moisture content on the activity of cellulase in AFEX-treated transgenic plants). The vessel was topped up with stainless steel pellets (approx 1 mm in diameter) to occupy the void space and thus minimize transformation of the ammonia from liquid to gas during loading, and then the lid was bolted shut. Using precalibrated ammonia sample cylinders, a predetermined amount of liquid ammonia was delivered to the vessel. The vessel was heated by a 400-W Parr heating mantle to the desired temperature. 

The remaining useful life evaluation routine (RULER) is a useful monitoring program for used engine oils. The RULER system is based on a voltammetric method (Jefferies and Ameye, 1997 Kauffman, 1989 and 1994). The data allows the user to monitor the depletation of two additives ZDDP and the phenol/amineH+ antioxidant. The RULER results were compared to other standard analytical techniques, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), total base number (TBN), total acid number (TAN), and viscosity to determine any correlation between the techniques (Jefferies and Ameye, 1997 and 1998). The test concluded that the RULER instrument can... 

As alluded to in the introduction, thermal analysis instruments must be calibrated using well-characterized materials. The melting of pure metals is the most common calibrant for DTA s and DSC s. Table 3.1 provides the melting temperature and latent heats of transformation of standard materials. The software in more contemporary instruments permit input of peak area values and onset temperatures determined by a test run, as well as values from the literature, into a program. It then automatically applies abscissa and ordinate corrections to all future data collected by the instrument. 

Theories and instrumentation of Fourier transform IR spectroscopy and electron spectroscopy for chemical analysis are briefly reviewed. The possibility of using these techniques in detection and analysis of acid impurities distributed at surfaces of paper documents produced during the period from 1790 to 1983 is demonstrated. Results show that all of the papers tested contained carboxylic groups. The carboxylic acids found in the paper of 1790 are the results of oxidation and aging. Acids in other papers are due to fiber oxidation as well as the presence of rosin acids. These techniques show promise as nondestructive methods for elucidating chemical characteristics of surfaces of paper documents. 

A problem that arises in many cases is that small raw data samples may contain one or more results which appear to be divergent from the remainder the problem may arise in a calibration experiment or in a set of replicate measurements on a test material. Assuming that the cause of the divergence is not immediately apparent e.g. as a result of a transcription error or instrument failure) it is then necessary to decide whether such an outlier can be rejected entirely from the raw data before data processing e.g. logarithmic transformations) and the usual statistical methods are applied. The treatment of outliers is a major topic in statistics. Three distinct approaches are available. ... 

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