UL 60974-1:2005 pdf download – Arc Welding Equipment Part 1: Welding Power Sources.
10.6 Inlet openings
Where the supply cable passes through metallic parts, it shall be provided with a bushing of insulating material, or the openings shall be smoothly rounded with a racus of at least 1.5 mm.
Conlormñ’y shall be checked by visual inspection
10.7 Input supply on/off switching device
Where an integral input supply on/off switching device (eg. switch. contactor or circuit-breaker) is provided, this shall:
a) switch all ungrounded mains conductors, and
b) plainly indicate whether the circuit is open or closed, and either
C) Be rated as follows:
— voltage: not less than the values given on the RATING plate.
— current: not less than the highest effective supply current as given on the RATING plate, or
d) be suitable for this application.
Conformity shall be checked by visual inspection: for C) Ifl accordance with other relevant standards, ana for d) by the following tests:
For the tests, it is permissible to use separate but duplicate switching devices.
A welding power source is connected for the RATED SUPPLY VO4,TAGE that corresponds to the RATED WXIIIUN SUPPLY CUR&NT arid, in addition for protection dass I, a fuse of 10 A to 20 A is placed
— in the case of an earthed input supply, in the protective earth connection;
— in the case of an unearthed input supply, between a supply line and the protective earth circuit.
Dunng the tests, the supply voltage shalt be maintained not less than at the RAIU Awk. a) Overload
The output of the welding power source is shol-circuited in accordance with 8.2. The switching device is operated for 100 cycles at the rate of 6 to 10 cycles per minute with a minimum on-time of 1 s. A switching device need not be tested if its RATING exceeds lwce the RATED MAXILId SUPPLY CURNT,
b) Endurance
The output is connected to a CONVENTIONAL ioAo and adjusted to produce the rated WELDING CURRENT at 100%. The switching device is operated for 1 000 cycles at a rate of 6 to 10 cycles per minute with a minimum on-time of 1 S.
111.4 RATED NO-LOAD VOLTAGE for special processes e.g. plasma cuthng The RATED NO-LOAD VOLTAGE shall not exceed 500 V peak d.c.
A RATED r-LOAO VOLTAGE exceeding 113 V peak d.c. may only be used if the following requirements are fulfilled.
a) These power sources with their corresponding torches shall prevent the output of NO-LOAD VOLTAGE if the torch is disassembled or disconnected from the power source.
b) The NO-LOAD VOi.ThOE shall be less than 68 V peak not later than 2 s after the corroi. CIRC4JIT (e.g. start switcth) is opened
C) The voltage between the tip of the torch and the work páece or earth shall not exceed 68 V peak when the arc current is interrupted, that is when both pilot and main arc are extinguished.
The conditions for complying with these requirements shall be given in the instructions.
Such power sources may be marked with the symbol £0.
Conformity shall be checked by measurement in accordance with 11.1. by operation and by visual inspection, except that the series combination of the 200 Q fixed arid 5 k1 variable resistors may be replaced by a fixed resistance of 5 kfl.
Throughout its range of adjustment, the welding power sources shall be capable of supplying oONvENnokA.
WELDING CURRENTS (p2) at CONVENTiONAL LOAD VOLTAGES (Ui) in accordance with 11.2.1 to 11.2.4.
Conformity shall be checked by sufficient measurements (see annex H).
11.2.1 Manual metal arc welding with covered electrodes.