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Current summations with current transformers
Journal of the Institution of Electrical Engineers, 1955The behaviour of current transformers in parallel, and of similar circuits employing summation transformers, is studied for different conditions of load distribution.After the existing theory concerning idle currents has been rejected it is demonstrated that the overall error is very nearly constant for a given total load, no matter how the current may
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A wideband current transformer bridge
2013 IEEE International Workshop on Applied Measurements for Power Systems (AMPS), 2013The work progress on a new current transformer test set at PTB is described. The operation range for the ratio based bridge is intended for frequencies from 16.7 Hz up to 20 kHz. Equal setups of magnetically shielded current comparators with primary windings for currents from 100 mA up to 5 A convert the secondary currents of the standard current ...
Enrico Mohns +4 more
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A Wideband Current Transformer Bridge
IEEE Transactions on Instrumentation and Measurement, 2014The development and testing results of a new current transformer (CT) test set at Physikalisch-Technische Bundesanstalt are described. The operation range for the ratio based bridge is intended for frequencies from 16.7 Hz up to 20 kHz. Equal setups of magnetically shielded current comparators with primary windings for rated currents from 100 mA up to ...
Enrico Mohns +3 more
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Methods for Testing Current Transformers
Transactions of the American Institute of Electrical Engineers, 1924In the sale of electric power especially in large amounts at high voltages, current transformers are universally used to operate the meters from the readings of which the bills are made out. While the secondary currents of such transformers reproduce fairly faithifully on a smaller scale the conditions of current strength and phase existing in their ...
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Current-mode network transformations
Proceedings of IEEE International Symposium on Circuits and Systems - ISCAS '94, 2002Current-mode network transformations are presented from which it is possible to generate new current-mode circuits by performing simple operations on the network. These transformations are developed by interchanging the ports of a current-mode circuit and exploiting the properties of current-conveyors and RC networks.
Mehul Desai +2 more
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Transformer magnetizing inrush currents
Electrical Engineering, 1951THERE ARE formulas available by which it is possible to calculate the peak of the first cycle of magnetizing inrush current for a transformer. There have been no convenient formulas available for determining the maximum values of successive cycles of current.
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The Phase Angle of Current Transformers
Transactions of the American Institute of Electrical Engineers, 1915A method of testing the phase angle of current transformers by comparing readings obtained on a wattmeter whose current circuit is first connected to receive a part of the primary current (the remainder of the primary current passing in shunt through resistance) and then connected to the secondary circuit; the potential circuit is supplied from the ...
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IEEE Transactions on Control Systems Technology, 2001
The measurement of the current in industrial electrical devices is often carried out by current transformers. The reliability of these devices is compromised when the measured current is higher than the nominal value, due to the saturation and hysteresis effects of the magnetic core.
BITTANTI, SERGIO +3 more
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The measurement of the current in industrial electrical devices is often carried out by current transformers. The reliability of these devices is compromised when the measured current is higher than the nominal value, due to the saturation and hysteresis effects of the magnetic core.
BITTANTI, SERGIO +3 more
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Harmonics in transformer magnetizing currents
Proceedings of the American Institute of Electrical Engineers, 1915The purpose of this paper is to show in a concise manner the cause and effects of higher harmonic currents in magnetizing currents of transformers. A hypothetical case is analyzed to show the cause of the harmonics; then the schemes of connecting transformers that are commonly used for polyphase transformation are taken up and the effects of the ...
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Computation of accuracy of current transformers
Electrical Engineering, 1940WHILE the general principles of the operation of current transformers have been known for some time, and tests have provided much experimental data, the introduction of high-speed relaying, especially differential protection, required a greater knowledge of currenttransformer performance than was necessary previously. It is the purpose of this paper to
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