BS 638-5:1988 pdf free download

06-15-2021 comment

BS 638-5:1988 pdf free download.Arc welding power sources , equipment and accessories Part 5 : Specification for accessories.
1.1 Scope
This part of BS 638 specifies requirements for accessories intended for use in arc welding processes.
NOTE The Lit Ics of the publications referred to in BS 638-5 are listed on the inside back cover.
1.2 Definitions
For the purposes of this part of BS 638, the following definitions apply. For other relevant terms the definitions in BS 499-1 apply.
NOTE All the electrical quantities specified in the definitions are those obtained under steady state conditions.
voltage reducing devke (voltage reducing system)
a device or system that automatically reduces the no-load voltage appearing at the output terminals of a welding power source during intervals when welding is not being performed and automatically restores the voltage to its unreduced value during welding
coupling device
a device to connect two flexible welding cables or to connect a flexible welding cable to a welding power source or to welding equipment
cable coupler
a device to connect two flexible welding cables consisting of two parts, which can be asymmetrical or symmetrical, as follows:
a) asymmetrical cable coupler (see Figure 1(a)). consisting of i) a connector (1), which is the female part:
ii) a plug (2), which is the male part;
b) symmetrical cable coupler [see Figure 1(b)J, consisting of two plug-connectors (3).
NOTE When using a symmetrical cable coupler, special care should be taken to make the correct connection.
3.1 Electrode heating quivers
3.1.1 Design and construction Quivers shall be so constructed as to withstand mechanical damage under normal working conditions without any metal case work making contact with the electrical elements. The quiver shall be fitted with a non.detachahle self.closing cover. The heating elements shall not be exposed such that they can be touched with a rod of 1 mm diameter (degree of protection of class IP4X in accordance with BS 5490). Terminals for the supply cables shall be enclosed. The maximum supply voltage for electrically heated quivers shall be 110 V. the maximum voltage to earth in the case of alternating current being 0 V. Quivers shall be supplied with connecting cables in accordance with Table 7 or Table 8 of BS 6500:1984. A means for securely anchoring these cables shall be incorporated in the quiver.
An earthing conductor shall be included unless the quiver is class II or class III as defined in BS 2754. Any spike, clamp or other device used for connection to the welding cable shall be insulated such that no live part can he touched. An enclosed fuse shall be part of the device or shall be fitted adjacent to the device. Any magnet, clamp or other device supplied for use in connecting the cable from the quiver to the work piece shall be insulated except for the clamping face. Quivers desigiwd for operation on supplies with a no-load voltage greater than 50 V shall have all metal parts which can be touched connected to the earth terminal unless of class II construction as defined in BS 2754. No external part of the quiver shall exceed the following temperatures when in use:
a) metal enclosures: 60 °C:
b) non-metallic enclosures: 80 °C;
c) metal handles: 50 °C;
d) non-metallic handles: 70°C. The internal temperature of the electrode storage compartment shall not exceed 150 °C.
3.1.2 Tests
4.2 Wire reels and spools
Wire reels and spools for wires for gas shielded arc welding shall comply with BS 2901.
Provision shall be made to attach a reel andlor spool cover in order that this cover can be fitted if required.
4.3 Water recirculating units7)
4.3.1 General
The requirements given in this clause shall apply to separate water recirculating units and to water
recirculating systems built into power sources.
4.3.2 Motors Motors shall be designed for continuous operation at the maximum load at both the maximum and the minimum rated speeds. They shall be so designed or protected that they are not damaged by abnormal load conditions. They shall also be protected against the ingress of water. In the case of electric motors, the brushes, if fitted, shall be readily replaceable without creating a hazard of electric shock.
4.3.3 Construction
Hoses, pipes and other components of the water recirculating system shall be arranged within the unit so that they do not become damaged during normal operation. They shall be capable of withstanding a temperature range of —25 °C to 100 °C and a pressure of at least 5 arS, except that the pressure requirement does not apply to the header tank.
Live parts shall be protected against the likelihood of escaping water.
4.3.4 Rating plate
The following shall be legibly and indelibly marked on the rating plate:
a) manufacturer’s name and address, manufacturer’s trademark (optional):
b) maximum pressure of cooling liquid;
c) maximum flow rate of cooling liquid:
d) maximum and minimum ambient temperatures: Sound levels. Sound levels shall not exceed 85 dBA.
6.6 Curtains and screens
6.6.1 The requirenient given in this clause shall apply to welding screens and curtains made from opaque or transparent material used to isolate a welding operation from adjacent personnel.
NOTE The intention of the acreena is to black or reduce to safe levels the ultravwlet (UV) radiation from the welding arc. They are not intended to replace welding helmets, handacreen and welding filters for close viewing of the welding arc.
The nature of the radiation from the arc and suitable protective filters are specified in BS 679.
6.6.2 The curtain or screen material shall be used as free hanging curtains or stretched on movable frames or as overlapping strips fixed to a frame or rail.
6.6.3 Opaque curtains made from cotton duck (canvas) or fibre reinforced plastics shall block completely all the radiation from the arc.
6.6.4 The materials used for the curtains and screens shall have a flammability performance as specified in BS 5867-2. type B using the test method specified in BS 54:18, test 2 with a flame application time of 15 a.
6.6.5 The material shall not deteriorate under the influence of incident arc radiation in the normal working poaition.
6.6.6 Transparent or translucent plastic screens and curtains shall have an optical density greater than 2, (transmittance less than 1 %), for all wavelengths less than 450 nm (see BS 679).
NOTE It is recommended that, in order to prevent temporary dazzle to spectators from high current arcs, the transparent material should have an optical density of I in the visible wavelengths greater than 450 nm and that the curtain should be at least I m from the arc.

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