Topic
Isolation transformer
About: Isolation transformer is a research topic. Over the lifetime, 8145 publications have been published within this topic receiving 72396 citations.
Papers published on a yearly basis
Papers
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23 Nov 1983
TL;DR: In this article, an electronic transformer system for illuminating neon lamps includes a counterphase oscillator coupled to a leakage reactance power transference transformer, which is powered by commercial alternating current through a full wave rectifier, or by a direct current power supply.
Abstract: An electronic transformer system for illuminating neon lamps includes a counterphase oscillator coupled to a leakage reactance power transference transformer. The power transference transformer has a secondary wound on a multiple section bobbin in which adjacent sections are separated from each other by a dielectric material. The leakage reactance power transference transformer has a feedback winding which is coupled in series to the primary winding of a pulse generator base driving transformer. The pulse generator base driving transformer in turn provides periodic pulses to the counterphase oscillator to reverse current flow in the primary of the leakage reactance power transference transformer. The electronic transformer system may be powered by commercial alternating current through a full wave rectifier, or by a direct current power supply.
30 citations
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21 Jun 1987TL;DR: In this paper, a novel type of the sinusoidal DC-AC converter is presented, where a pair of switches is placed in each side of the primary and the secondary of the isolation transformer.
Abstract: A novel type of the sinusoidal DC-AC converter is presented, where a pair of switches is placed in each side of the primary and the secondary of the isolation transformer. This converter is controlled by the phase difference between the two pairs of switches. As a result, the transformer is miniaturized by making the switching frequency high. This converter is especially suitable for small UPS systems.
30 citations
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10 Mar 1998
TL;DR: In this paper, a composite bridge amplifier with a non-ground reference DC voltage supply dependant on the input signal is presented, and safety isolation is provided by configuring the isolation amplifier so that currents charging the parasitic capacitance with common mode noise voltage tend to cancel noise current in the secondary winding of the transformer.
Abstract: A composite bridge amplifier in which the power supply for the bridge amplifiers includes a time varying non-ground reference DC voltage supply dependant on the input signal. A low voltage power supply circuit uses the time varying non-ground reference DC voltage to produce a fixed DC voltage and includes a centering block which removes unbalanced DC voltages which might otherwise contaminate the time varying non-ground reference DC voltage, by providing balancing currents. This eliminates a costly transformer. Safety isolation is provided using an isolation amplifier with a transformer which has a parasitic capacitance. Improved common mode noise rejection is provided by configuring the isolation amplifier so that currents charging the parasitic capacitance with common mode noise voltage tend to cancel noise current in the secondary winding of the transformer.
30 citations
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TL;DR: In this paper, the authors present results of voltage distribution measurements performed on model windings with different constructions subjected to voltages with different rise time, allowing for investigation of influence of the dielectric (air/oil) and temperature on the stress distribution along the winding.
Abstract: Evolution and operation of modern grids and networks necessitate reconsideration of several characteristics. For example transformers operating in power grid or in industrial environment are subjected nowadays also to transients or stimulus with different waveforms. Traditionally, in case of power transformers the stresses are related to lightning and switching phenomena. In industrial networks distribution transformers are exposed to many switching operations generating often overvoltages. Transformer windings subjected to such system disturbances are stressed due to the non-linear transient voltage distribution along the winding and potential resonance phenomena. Initial voltage distribution, reflects mainly the capacitive coupling between turns, windings, core and tank. The non-uniform distribution of voltage results in concentred stress in certain parts of the winding. Winding resonance might occur, if the frequency spectrum of incoming surge matches the winding natural frequencies. Therefore external transients occurring in power systems might trigger internal overvoltages with large maximum value in transformer windings. The frequency characteristic of the transformer winding may determine those regions in the frequency spectrum. The paper presents results of voltage distribution measurements performed on model windings with different constructions subjected to voltages with different rise time. The experimental setup allows for investigation of influence of the dielectric (air/oil) and temperature on the stress distribution along the winding. Also the impact of oil and temperature on frequency characteristics of internal voltages are shown. The presented results might be used both for design and optimization of transformers windings.
30 citations
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05 Feb 2010TL;DR: In this article, a hybrid transformer is provided that includes an electromagnetic transformer and an AC-AC converter with a DC bridge, which is operable to keep the input voltage and current of the hybrid transformer substantially in phase.
Abstract: A hybrid transformer is provided that includes an electromagnetic transformer and an AC-AC converter with a DC bridge. The AC-AC converter is operable to keep the input voltage and current of the hybrid transformer substantially in phase and to reduce fluctuation in the output voltage of the hybrid transformer in the event of an increase or decrease in the input voltage.
30 citations