BS EN IEC 60974-2:2019 pdf download – Arc welding equipment Part 2: Liquid cooling systems (IEC 60974-2:2019).
1 Scope This part of IEC 60974 specifies safety and construction requirements for industrial and professional LIQUID COOLING SYSTEMS used in arc welding and allied processes to cool torches. This document is applicable to LIQUID COOLING SYSTEMS which are stand-alone (separate from the welding equipment) or built-in (housed in a single enclosure with other welding equipment). This document is not applicable to refrigerated cooling systems. NOTE 1 Typical allied processes are electric arc cutting and arc spraying. NOTE 2 This part of IEC 60974 does not include electromagnetic compatibility (EMC) requirements that are given in IEC 60974-1 0. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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. IEC 60974-1 :201 7, Arc welding equipment – Part 1: Welding power sources IEC 60974-7:201 3, Arc welding equipment – Part 7: Torches IEC 60974-1 0:201 4, Arc welding equipment – Part 10: Electromagnetic compatibility (EMC) requirements 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60974-1 and IEC 60974-7 and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp
4 Environmental conditions As specified in Clause 4 of IEC 60974-1 :201 7. 5 Tests 5.1 Test conditions As specified in 5.1 of IEC 60974-1 :201 7. Stand-alone cooling systems may be tested without a welding power source. Built-in cooling systems shall be tested with the welding power source. 5.2 Measuring instruments The accuracy of measuring instruments shall be: a) electrical measuring instruments: class 1 (± 1 % of full-scale reading), except for the measurement of insulation resistance and dielectric strength where the accuracy of the instruments is not specified, but shall be taken into account for the measurement; b) thermometer: ± 2 K; c) pressure measuring instruments: class 2,5 (± 2,5 % of full-scale reading); d) flow-rate measuring instruments: class 2,5 (± 2,5 % of full-scale reading). 5.3 Conformity of components As specified in 5.3 of IEC 60974-1 :201 7. 5.4 Type tests All type tests shall be carried out on the same cooling system unless specified otherwise.
6 Protection against electric shock 6.1 Insulation 6.1.1 General As specified in 6.1 .1 of IEC 60974-1 :201 7. 6.1.2 Clearances As specified in 6.1 .2 of IEC 60974-1 :201 7. 6.1 .3 Creepage distances As specified in 6.1 .3 of IEC 60974-1 :201 7. 6.1.4 Insulation resistance As specified in 6.1 .4 of IEC 60974-1 :201 7. The test may be carried out without cooling liquid. 6.1.5 Dielectric strength As specified in 6.1 .5 of IEC 60974-1 :201 7. The test may be carried out without cooling liquid. 6.2 Protection against electric shock in normal service (direct contact) As specified in 6.2 of IEC 60974-1 :201 7. 6.3 Protection against electric shock in case of a fault condition (indirect contact) 6.3.1 Protective provisions As specified in 6.3.1 of IEC 60974-1 :201 7. 6.3.2 Isolation between windings of the supply circuit and the welding circuit As specified in 6.3.2 of IEC 60974-1 :201 7. 6.3.3 Internal conductors and connections As specified in 6.3.3 of IEC 60974-1 :201 7. 6.3.4 Touch current in fault condition As specified in 6.3.6 of IEC 60974-1 :201 7. 6.4 Connection to the supply network 6.4.1 Supply voltage As specified in 1 0.1 of IEC 60974-1 :201 7.
6.4.7 Inlet openings As specified in 1 0.7 of IEC 60974-1 :201 7. 6.4.8 Supply circuit on/off switching device As specified in 1 0.8 of IEC 60974-1 :201 7. 6.4.9 Supply cables As specified in 1 0.9 of IEC 60974-1 :201 7. 6.4.1 0 Supply coupling device (attachment plug) If a supply coupling device is provided as a part of the LIQUID COOLING SYSTEM , its rated values shall be not less than the maximum effective supply current I 1 eff . For supply networks up to 1 25 V, the rated current shall, additionally, not be less than either a) or b): a) 70 % of the rated maximum supply current; b) 70 % of the supply current, as measured with the fan motor or pump stalled, whichever is greater. Conformity shall be checked by visual inspection, measurement and calculation. 6.5 Leakage current between welding circuit and protective earth With the cooling system filled with the cooling liquid specified by the manufacturer (see 1 2.1 e)), the leakage current from the torch to the protective earth connection of the cooling system shall not exceed 1 0 mA DC. Conformity shall be checked by applying a DC voltage of 500 V at room temperature between the protective earth connection and a copper pipe to simulate the torch connected to the outlet of the cooling system by a hose with a maximum length of 0,5 m as shown in Figure 1 . The minimum inner diameter of the hose shall be 5 mm. The minimum length of the copper pipe shall be 10 cm with a minimum internal diameter of 5 mm. The cooling system and the simulated torch are filled with liquid for the test. The pump is operating. BS EN IEC 60974-2:2019 – 1 0 – IEC 60974-2:201 9 © IEC 201 9 NOTE The design of the torch can influence the leakage current value; therefore, a conventional copper pipe is used to simulate the torch during the conformity test. Key 1 L IQUID COOLING SYSTEM 2 Hose 3 Copper pipe Figure 1 – Leakage current measurement configuration 7 Mechanical provisions 7.1 General As specified in Clause 1 4 of IEC 60974-1 :201 7. The test shall be carried out with cooling liquid. 7