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    The origins of 60-Hz as a power frequency

    Owen, E.L.
    Industry Applications Magazine, IEEE

    Volume: 3 , Issue: 6
    DOI: 10.1109/2943.628099
    Publication Year: 1997 , Page(s): 8, 10, 12 - 14
    Cited by:  Papers (5)

    IEEE Journals & Magazines

    In 1891, Westinghouse engineers in Pittsburgh selected 60 Hz as their new power frequency. That same year, AEG engineers in Berlin selected 50 Hz as their new power frequency. Although much has happened since 1891, these two frequencies remain the principal power frequencies in use worldwide. Many people continue to be affected by the decisions on frequency standards made so very long ago. The author discusses the origins of 60 Hz as the power frequency now used in the USA. The author covers the work of Charles Scott, Benjamin Lamme and L.B. Stillwell of Westinghouse, the experimental period of 1821 to 1880, the light period from 1880 to 1890, the power and period of 1890 to 1925, and the period of systems interconnection from 1925 to 1990. Particular emphasis is given to the development of frequency for lighting systems and of frequency development in the USA, Europe and Japan View full abstract»

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    Dependence of losses on flux density in grain oriented 3% silicon steel

    Washko, S.D. ; Shilling, J.
    Magnetics, IEEE Transactions on

    Volume: 16 , Issue: 5
    DOI: 10.1109/TMAG.1980.1060724
    Publication Year: 1980 , Page(s): 737 - 739
    Cited by:  Papers (2)

    IEEE Journals & Magazines

    Samples of conventional and high permeability grain oriented 3% silicon-iron were tested at flux densities of 1.0, 1.3, 1.5 and 1.7 T. The losses of selected samples were also measured at magnetizing frequencies of 30, 40 and 50 Hz in addition to 60 Hz. Results show that losses increase simply as the square of induction from 1.0 to 1.3 T regardless of sample history, degree of texture perfection, thickness, or grade. Such a dependence of losses on flux density is predicted by all domain theories of eddy current losses in these materials. However, such a simple dependence of losses on the square of flux density does not persist up to 1.7 T. Instead, losses at 1.7 T are offset from a theoretical B2dependence by a constant amount (Δ Ps) which depends only on the degree of texture perfection (i.e., μ10 or B at 800 A/m). This some what surprising result is true regardless of sample history, sheet thickness, grade, or frequency. The origin of this effect is discussed and factors affecting low induction core loss are summarized. View full abstract»

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    The origin and characterization of the primary signal, noise, and interference sources in the high frequency electrocardiogram

    Santopietro, R.F.
    Proceedings of the IEEE

    Volume: 65 , Issue: 5
    DOI: 10.1109/PROC.1977.10551
    Publication Year: 1977 , Page(s): 707 - 713
    Cited by:  Papers (11)  |  Patents (1)

    IEEE Journals & Magazines

    An analysis technique was developed that enabled accurate measurement of the spectral and spatial characteristics of the predominant signal, noise, and interference components in high frequency electrocardiograms. A selective sampling technique, utilizing the isoelectric interval during the T-P segments, enabled the charactetistics of the internally generated noise and external interference to be obtained independently of the heart signal. Using this sampling technique, it was found that the electrical activity of skeletal muscles was the major source of noise in the high frequency electrocardiogram. The amounts of skdetal muscle noise present in the high frequency electrocardiograms of resting patients were measured quantitatively through the use of anesthetics and muscle relaxant drugs. In the normal resting state, the electrical activity of skeletal muscles contributed up to 15 dB of random noise to the spectra of waveforms generated by the electrical activity of the heart. Moderate, voluntary contraction of small groups of skeletal muscles increased their electrical output by 15 to 20 dB. Spectral analysis of high frequency electrocardiograms indicated that a dynamic range of approximately 66 dB is requized to adequately measure the signal and noise components present. Power spectra of high frequency electrocardiograms indicated that the 60-Hz power lines were the major source of interference Harmonics of the 60-Hz power line added significant interference components at frequencies as high as 1 kHz. The magnitude-squared coherence function between pairs of electrocardiographic leads, in conjunction with segment sampling and analysis techniques, was used to measure the spatial coherence of waveforms from electrical source associated with heart and skeletal muscle activity. The high values of spatial coherence of heart signal waveforms indicated that the body spatial transfer functions for electrical sources associated with heart activity acted as linear, noiseless transmission channels. The low spatial coherence of the waveforms generated by the electrical activity of skeletal muscles indicated that the body spatial transfer functions for electrical sources associated with skeletal muscle activity acted as noisy (nondeterministic) transmission channels. Th- e spatial coherence of isoelectric interval waveforms was inversely proportional to both the distance between measurement sites and the amount of skeletal muscle activity. View full abstract»

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    Technical origins of 60 Hz as the standard AC frequency in North America

    Mixon, P.
    Power Engineering Review, IEEE

    Volume: 19 , Issue: 3
    DOI: 10.1109/MPER.1999.1036103
    Publication Year: 1999 , Page(s): 35 - 37
    Cited by:  Papers (2)

    IEEE Journals & Magazines

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