Telephone: +41 22 02 11 Telefax: +41 22 03 00 E-mail: [email protected] Web: INTERNATIONAL. STANDARD. IEC. Third edition. This part of IEC identifies the requirements for power transformers to sustain without damage the effects of overcurrents originated by external short. IEC. Second edition. This English-language version is As from 1 January all IEC publications are issued with a designation in the.
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The test shall be carried out in accordance with the requirements in 4.
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CombiWizard Identifies the products compatible with Scame material. These measurements and tests serve as references for the detection of faults. Particular requirements and tests for isolating transformers and power supply units incorporating isolating transformers IEC Safety of transformers, reactors, power supply units and similar products for supply voltages up to 1 V Part Particular requirements and tests for auto transformers and power supply units incorporating auto transformers.
However, these high values are iex, in the two limbs concerned, to a half of the coil and furthermore the currents in the other star-connected winding are lower than for a three-phase short circuit.
Annex B forms an integral part of this standard. General requirements for basic safety and essential performance IEC Safety of power transformers, power supplies, reactors and similar products Part 1: Information relating to this publication, including its validity, is available in the IEC Catalogue of publications see below in addition to new editions, amendments and corrigenda.
Table of physical and chemical constants — Kay and Laby — 15 edition, Longmans, The factor k accounts for the initial offset of the test current and to-r. Unless otherwise specified, the three tests on a single-phase transformer with tappings are made in a different position of the tap-changer, i.
Annex A is for information only.
If this 6076-5 not the case, a single-phase supply, as described below, may be used. Particular requirements for separating transformers for general use. If the pre-set short circuit is used for a transformer with single-concentric windings, the supply should preferably be connected to the winding further from the core.
Particular requirements and tests for control transformers and power supplies incorporating control transformers. Furthermore, the outside of the transformer under test shall be observed visually and continuously video recorded.
These iecc and reactance limits are given in the following items a and b. These characteristics shall be specified by the purchaser in his enquiry. Another method for determining the phase current in a delta-connected winding is by suitably interconnecting the secondary windings of the current transformers measuring the ice currents.
This last value of reactance is accepted as the final value when determining compliance with the requirements of the standard. Guidance for the identification of a similar transformer is given in annex A.
In such cases, ie overcurrent level must be limited by appropriate means, such as series reactors or, in some instances, fuses. Q5 This standard meets my needs: NOTE It may not be economical to design auxiliary windings to withstand short circuits on their terminals.
NOTE Equations 4 and 5 are based on adiabatic conditions and are valid for only a short time duration, not exceeding 10 s.
For other transformers with star-zigzag connection, the method of switching on is subject to agreement between the manufacturer and the purchaser. Particular requirements for isolating transformers for the supply of medical locations. Safety of power transformers, power supplies, reactors and similar products Part 1: For example, edition numbers 1. MBOX Series for construction site.
U and Z t are defined as follows: NOTE 1 Additional means of detection may be used to obtain information and improve the evaluation of the test event, such as recording of the current between the tank insulated and earth, recordings of noise and vibrations, recordings of oil pressure variations occurring at different locations inside the tank during short-circuit current flow, etc.
Protection accessories, such as a gas-and-oil-actuated relay and pressure relief device, iiec be mounted on the transformer during the test.
INTERNATIONAL STANDARD IEC 60076-5
NOTE 1 At the end of the tests, if the windings are provided with tapping, the reactance must be measured for all the tapping positions at which the short-circuit tests have been carried out. There may be also a certain change of reactance with time after the tests.
For transformers having more than two windings, auto-transformers, booster transformers and transformers directly associated with other apparatus, the overcurrents are calculated in accordance with 3. All International European Italian. The oscillograph can be set to record 6076-5 phase currents. The peak value of the short-circuit current shall be calculated in accordance with 4.