BS EN IEC 60974-2:2019 pdf free.Arc welding equipment Part 2: Liquid cooling systems (IEC 60974-2:2019).
A cooling system shall not break down and increase the risk of electric shock or fire under theconditions of operation of 9.2. These tests are conducted without regard to temperatureattained on any part,or the continued proper functioning of the cooling system. The onlycriterion is that the cooling system does not become unsafe. These tests may be conductedon any cooling system that functions correctly.
The cooling system,protected internally by, for example,a circuit-breaker or thermalprotection,meets this requirement if the protection device operates before an unsafecondition occurs.
Conformity shall be checked by the following tests.
a) A layer of dry absorbent surgical type cotton is placed under the cooling system,extending beyond each side for a distance of 150 mm.
b) Starting from the cold state, the cooling system is operated in accordance with 9.2.
c) During the test, the cooling system shall not emit flames,molten metal or other materials that ignite the cotton indicator.
d) Following the test and within 5 min, the cooling system shall be capable of withstanding a dielectric test in accordance with 6.1.5 b) of lEC 60974-1:2017.
9.2Stalled test
A cooling system,which relies on motor-driven fan(s) and pump(s) for conformity with thetests of 8.2, is operated at rated supply voltage or rated load speed for a period of 4 h whilethe fan motor(s) and pump(s) is(are) stalled,or running without cooling liquid,or disabled,which produces the maximum heating.
NOTE The intention of this test is to run the cooling system with the fan stationary. The fan can be blockedmechanically or disconnected.
CooLING POwER data shall be given in kW for 100 % duty cycle,with the cooling liquid asrecommended by the manufacturer and at an ambient air temperature at 25 °℃ (seetolerances of test parameters in 8.2.2).For these values the volume flow shall be 1 l/min.
This test may be carried out on a separate cooling system.
A built-in cooling system may additionally be heated by the welding power source.Thereforethe test shall be performed together with the welding power source, set for maximum heating.
This test is not required for LlQuID COOLING SYSTEMs specified by the manufacturer to be usedonly with dedicated torches.Conformity shall be checked by the following test and calculation:
a) the LlauID cooLING SYSTEM is filled with the amount and type of cooling liquid recommended in the manufacturer’s instructions (see 12.1 e));
b) the LlQuID cOOLING SYSTEM is connected to a measuring circuit according to Figure 2;
c) the valve is adjusted to obtain a flow of 1 lmin (see tolerances of test parameters in 8.2.2);
In the case of built-in cooling systems, section c) of Figure 3 shall be added to the rating plate of the welding power source, as specified in Clause 15 of lEC 60974-1:2017.BS EN IEC 60974-2 pdf download.