Topic
Isolation transformer
About: Isolation transformer is a research topic. Over the lifetime, 8145 publications have been published within this topic receiving 72396 citations.
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TL;DR: In this paper, power transformers are considered to be the heart of the transmission and distribution sectors of electric power systems; monitoring their condition and diagnosing faults are important parts of the maintenance function.
Abstract: Power transformers are in service under different environmental, electrical, and mechanical conditions [1] and may be subject to enormous hazards during the course of operation [2], [3]. They are commonly considered to be the heart of the transmission and distribution sectors of electric power systems; monitoring their condition and diagnosing faults are important parts of the maintenance function [4]. Utility engineers strive to keep power transformers in service and to prevent even shortterm outages. Failure of a transformer can cause extensive damage to equipment owned by consumers or the utility [5].
144 citations
Patent•
03 Dec 1993
TL;DR: In this paper, a method and apparatus for communicating a modulated signal across an isolation barrier using capacitors is provided. But this method requires the use of a large and bulky isolation transformer.
Abstract: A method and apparatus for communicating a modulated signal across an isolation barrier using capacitors is provided. The present invention allows low distortion communication of an audio signal across an isolation barrier without the need for a large and bulky isolation transformer. The present invention may be used to provide telephone line isolation for modem applications compliant with governmental regulations. A line interface integrated circuit (IC) may be connected directly to a telephone line and powered by the telephone line. The line interface IC may include a sigma delta modulator to communicate the receive signal across a capacitor over an isolation barrier and a digital-to-analog (D/A) converter to provide an analog transmit signal from a sigma delta bit stream communicated across a capacitor over an isolation barrier. Circuitry on the opposite side of the isolation barrier includes similar components to process the transmit and receive signals.
144 citations
Patent•
13 Nov 1990
TL;DR: In this article, a high frequency AC electro-surgery apparatus is equipped with an automatic regulation loop for controlling the output voltage (Ua) rather than the output power, and an electrically isolating coupling in the form of an isolation transformer is followed by a voltage converter to provide DC voltage signal (a) proportional to a measure of the high-frequency AC output voltage(Ua).
Abstract: A high frequency AC electro-surgery apparatus is equipped with an automatic regulation loop for controlling the output voltage (Ua) rather than the output power. An electrically isolating coupling in the form of an isolation transformer (5) is followed by a voltage converter (6) to provide DC voltage signal (a) proportional to a measure of the high frequency AC output voltage (Ua). The DC voltage signal (a) is supplied to a regulating amplifier (7) to which a reference voltage signal (b) is supplied by a reference voltage source (8), to produce an output signal (c) that is furnished to the control input of an electronically controlled power supply (16). The latter controls the operating voltage (Ub) for the amplifier (2) of the high frequency AC generator in such a manner that the output AC voltage (Ua) at the output terminals (10, 11) corresponds to a desired value set by the reference voltage signal (b).
143 citations
TL;DR: In this article, the effects of various faults on the FRA signatures of a transformer simulated by a high-frequency model were analyzed and the faults were simulated through changes in the values of some of the electrical components in the model.
Abstract: This paper presents a comprehensive analysis of the effects of various faults on the FRA signatures of a transformer simulated by a high-frequency model. The faults were simulated through changes in the values of some of the electrical components in the model. It was found that radial displacement of a winding alters the FRA signature over the entire frequency range (10 Hz-1 MHz), whereas changes due to axial displacement occur only at frequencies above 200 kHz. A Table listing various transformer faults and the associated changes in the FRA signature was compiled and could be used in the formulation of standard codes for power transformer FRA signature interpretation.
143 citations
07 Aug 2002
TL;DR: In this paper, an actively cooled high power, high frequency transformer with high insulation capability for use in a high power multilevel converter is discussed, which is designed for a power level of 350 kW and is realized with amorphous core material and coaxial windings.
Abstract: An actively cooled high power, high frequency transformer with high insulation capability for use in a high power multilevel converter is discussed. The transformer is designed for a power level of 350 kW and is realized with amorphous core material and coaxial windings. Special attention is paid to the insulation problem, since the dielectric losses and the influence of the voltage waveform with very steep edges have to be investigated more in detail to guarantee a long lifetime of the device.
141 citations