Isolation transformers are also used for the power supply of devices not at ground potential. ![]() Supply of equipment at elevated potentials Often the system must additionally be designed so that fault conditions do not interrupt power, but generate a warning. With the transformer, as there is no conductive connection between transformer secondary and primary, only a small leakage current will flow if the exposed live metal is connected to earth.Įlectrical isolation is considered to be particularly important on medical equipment, and special standards apply. Without it, exposed live metal in a device under test is at a hazardous voltage relative to grounded objects such as a heating radiator or oscilloscope ground lead (a particular hazard with some old vacuum-tube equipment with live chassis). In electronics testing and servicing, an isolation transformer is a 1:1 (under load) power transformer used for safety. ![]() Some small transformers are used for isolation in pulse circuits. This may be another winding or a metal strip surrounding a winding.ĭifferential noise can magnetically couple from the primary to the secondary of an isolation transformer, and must be filtered out if a problem occurs.Īpplications Pulse transformers Halo TG110-S050N2RL 10/100BASE-TX Ethernet pulse transformer in SO-16 package A grounded Faraday shield between the primary and the secondary greatly reduces the coupling of common-mode noise. The capacitance between primary and secondary windings would also couple AC current from the primary to the secondary. Isolation transformers are designed with attention to capacitive coupling between the two windings. Only transformers whose primary purpose is to isolate circuits are routinely described as isolation transformers. Power transformers with specified insulation between primary and secondary are not usually described only as "isolation transformers" unless this is their primary function. Sometimes the term is used to emphasize that a device is not an autotransformer whose primary and secondary circuits are connected. Some specifications require that Isolation transformers be a part of the lightning protection on the AC circuits. Isolation transformers with electrostatic shields are used for power supplies for sensitive equipment such as computers, medical devices, or laboratory instruments. Suitably designed isolation transformers block interference caused by ground loops. Transformers that have a ratio of 1 to 1 between the primary and secondary windings are often used to protect secondary circuits and individuals from electrical shocks between energized conductors and earth ground. ![]() Isolation transformers block transmission of the DC component in signals from one circuit to the other, but allow AC components in signals to pass. A transformer sold for isolation is often built with special insulation between primary and secondary, and is specified to withstand a high voltage between windings. ![]() This isolation is used to protect against electric shock, to suppress electrical noise in sensitive devices, or to transfer power between two circuits which must not be connected. Isolation transformers provide galvanic isolation no conductive path is present between source and load. The grounded shield prevents capacitive coupling between primary and secondary windings.Īn isolation transformer is a transformer used to transfer electrical power from a source of alternating current (AC) power to some equipment or device while isolating the powered device from the power source, usually for safety reasons or to reduce transients and harmonics. JSTOR ( September 2010) ( Learn how and when to remove this template message)Ī 230 V isolation transformer A simple 1:1 isolation transformer with an extra dielectric barrier and an electrostatic shield between primary and secondary.Unsourced material may be challenged and removed.įind sources: "Isolation transformer" – news Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
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