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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12 Dec 2007TL;DR: In this article, a method and circuit for reducing power consumption in a power transformer, typically incorporated into an electrical or electronic device such as a consumer device, is presented. But the method is limited to the case where the power transformer senses the occurrence of no-load conditions in the transformer and responsively disengages from a coupled source of power (e.g., wall outlet).
Abstract: A method and circuit is provided for reducing power consumption in a power transformer, typically incorporated into an electrical or electronic device such as a consumer device. In an embodiment, a detection/isolation circuit is coupled to an input of a power transformer/rectifier via a switching device. The switching device can be, for example, a solid state relay. The detection/isolation circuit is configured to sense the occurrence of no-load conditions in the power transformer and responsively disengage the power transformer from a coupled source of power (e.g., wall outlet) via the coupled switching device.
32 citations
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11 Apr 1988TL;DR: In this article, a two-output DC-to-DC converter is studied using only a power transistor, and both outputs have been regulated by controlling duty cycle and switching frequency.
Abstract: A novel two-output DC-to-DC converter is studied. Using only a power transistor, both outputs have been regulated by controlling duty cycle and switching frequency. The number of power components is very low, as the use of demagnetizing components of the isolation transformer is avoided. A static and dynamic study of the converter has been carried out, and the results are verified for a prototype. >
32 citations
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22 May 2008
TL;DR: In this paper, a useful model of transformer under harmonic condition is presented, which includes a potential difference defined as the second derivative of the load current that represents eddy current losses in windings and the other stray losses represented as a resistor in series with the leakage inductance and dc resistance.
Abstract: Transformers are normally designed and built for utilizing at rated frequency and prefect sinusoidal loads. Supplying non-linear loads by transformer leads to higher losses, early fatigue of insulation, and reduction of the useful life of transformer. To prevent these problems rated capacity of transformer supplying non-linear loads must be reduced. In this paper, at first, a useful model of transformer under harmonic condition is presented. The model in addition to ordinary parameters includes a potential difference defined as the second derivative of the load current that represents eddy current losses in windings and the other stray losses represented as a resistor in series with the leakage inductance and dc resistance. Finally, losses and capacity of 50 KVA transformer under harmonic load current is calculated. This model simulated in MATLAB/Simulink and then its results are compared with losses and capacity calculated by standard.
32 citations
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15 Sep 1998TL;DR: In this article, the authors propose a line balance assessment for each sub-channel carrier within the system to avoid spurious energy radiation from a wireline communication resource supporting data over voice, such as in xDSL.
Abstract: To avoid spurious energy radiation from a wireline communication resource (42-44) supporting data over voice, such as in xDSL, modems (40, 46) supporting a multi-carrier transmission scheme undertake a line balance assessment (136-138) for each sub-channel carrier within the system. Specifically, an addressed modem (40) measures, for example, the signal to noise ratio of a differential transmission mode and a common transmission mode to provide the balance assessment (138). More particularly, a receive chain in the addressed modem is selectively switched (84) to receive the differential mode as appearing across the terminals of an isolation transformer (66) or the common mode (as seen with respect to ground) from a center tap (88) in a line-side winding (70) of the isolation transformer (66). Any sub-channel carrier that fails to provide a predetermined level of balance (140) is de-selected (141) by the modem and not used for traffic. Generally, the modems (40, 46) at both ends of the wire-line connection (42-44) notify one another of selected sub-channels, while the concept can be employed in a dynamic in-call fashion (152, 158-160).
32 citations
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23 Jun 1969
TL;DR: A transistorized electrical sleep-inducing device includes a current regulating buffer which protects the patient from excessive current, when operated on conventional AC power and maintains the current substantially constant regardless of variations in the patient's body resistance as discussed by the authors.
Abstract: A transistorized electrical sleep-inducing device includes a current regulating buffer which protects the patient from excessive current, when operated on conventional AC power and maintains the current substantially constant regardless of variations in the patient's body resistance. The patient is also protected by sensitive fuses, an isolation transformer, careful grounding, a floating circuit and a substantial resistance connected in series with him. A peak reading volt meter precisely indicates the pulse amplitude by utilizing a peak detector circuit connected to a high input impedance, such as balanced bipolar transistors or a unipolar field effect transistor (FET) differential amplifier. A frequency band selector and scanner, connected to the pulse generator, varies the applied frequency to suit the patient's response. The output is contacted to various portions of the patient's anatomy in accordance with his particular symptoms and treatment therefor.
32 citations