【導(dǎo)讀】Incorporating. useinthepresenceof. bustibledust—。BritishStandard. ICS. 15758. 16958. BSEN61241-1:2020. Nationalforeword. legalobligations.13January2020. ©BSI2020. ISBN058045200X. NORMEEUROPÉENNE. EUROPÄISCHENORMJune2020. ICS. Englishversion. enprésencedepoussièresbustibles. CzechRepublic,Denmark,Estonia,Finlan

　　

【正文】 Tests for dust exclusion by enclosures General Depending on the environmental conditions likely to be encountered (such as area classification and conductivity of dust) two levels of dust exclusion efficiency have been adopted: ―dusttight‖ and ―dustprotected‖ enclosures. NOTE For the required degree of dust exclusion efficiency, see IEC 6124114. In making an assessment for the acceptance of the apparatus following the tests, the effect of the presence of a bustible dust shall be taken into consideration. The precautions that shall be taken where a bustible dust is used for the tests is left to the discretion of the testing authority or others concerned. Dusttight apparatus for practice A Enclosures, including rotating machines, shall satisfy the requirements for IP6X, as specified in IEC 60529. Dustprotected apparatus for practice A All enclosures, including rotating machines, shall satisf y the test and acceptance requirements of IP5X, as specified in IEC 60529. Page 12 EN 61241?1:2020 Dusttight apparatus for practice B Heat cycling test a) The apparatus shall be mounted in a test chamber of sufficient size to permit free circulation of the dustair mixture around the sample during the test. A mixture of suitable dust and air shall be circulated by auxiliary equipment and introduced continuously into the test chamber during the entire test period. The particle size of the dust shall be such that it passes through a No. 100 ASTM sieve (approximately 0,15 mm mesh width) with approximately 22 % passing through a No. 200 ASTM sieve (approximately 0,075 mm mesh width). b) For the test specified above, the apparatus shall be operated at rated load until maximum temperatures are reached and then disconnected from the supply until it has cooled to approximately room temperature. The number of cycles of heating and cooling shall be at least six and shall last for a minimum of 30 h. NOTE 1 The maximum temperature under load may be obtained by other means than running at rated load. For an enclosure such as a junction box without any appreciable heating effect (. a switch), the effect of changes in barometric pressure may be simulated to produce the desired ―breathing‖ effect. NOTE 2 Heating the chamber to 40 176。C and maintaining this temperature for approximately 1 h and subsequently cooling the chamber to 20 176。C and maintaining this temperature for 1 h has been found to be a satisfactory method for simulating changes in barometric pressure. W hen the required number of heating and cooling cycles has been pleted, the equipment for producing the dustair atmosphere shall be shut off and the accumulated dust shall be removed from the exterior surfaces of the enclosures by gently brushing, wiping or shaking, with care being taken to avoid the introduction of additional dust into the enclosures. Under no circumstances shall the dust be removed by an air blast or by vacuum cleaning. The enclosure shall then be opened and carefully examined for the degree of dust peration if any. Acceptance criteria No visible dust shall have entered the enclosure. Dust in joints shall not be considered a failure. Dust protected apparatus for practice B Heat cycling test Proceed as described in except the number of cycles of heating and cooling shall be at least two and for a minimum period of 10 h. Acceptance criteria No visible dust shall have entered the enclosure. Dust in joints shall not be considered a failure. Page 13 EN 61241?1:2020 Thermal tests Apparatus for practice A This test shall be carried out as described in of IEC 612410. Apparatus for practice B This test shall be carried out in accordance with to of IEC 612410 with the additional requirement that the apparatus shall be covered with the maximum amount of dust that it can retain. As an alternative, a 12,5 mm thick layer of dust paste may be put on top of the apparatus to simulate the buildup conditions. NOTE The paste should consist of 45 % dust (. wheat flour) and 55 % water by weight. The temperature value should be measured after the paste has dried. 9 Marking Clause 29 of IEC 612410 applies except as follows: , item 4: The sym bol for the type of protection used shall be ―tD‖ (protection by enclosure). , item 5: The zone in which the apparatus can be used is prefixed by ―A‖ for practice A and ―B‖ for practice B. , item 6: Practice B does not need to include the IP rating. Page 14 EN 61241?1:2020 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE Where an international publication has been modified by mon modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60529 1989 Degrees of protection provided by enclosures (IP Code) EN 60529 + corr. May 1991 1993 A1 1999 A1 2020 IEC 612410 1) Electrical apparatus for use in the presence of bustible dust Part 0: General requirements 1) To be published. Page 15 EN 61241?1:2020 Annex ZZ (informative) Coverage of Essential Requirements of EC Directives This European Standard has been prepared under a mandat