BS 638-10:1990

Foreword
Section one. General
1. Scope
2. Object
3. Environmental conditions
4. Definitions
4.1 Arc welding power source
4.2 Industrial and professional use
4.3 Skilled person
4.4 Instructed person
4.5 Type test
4.6 Routine test
4.7 General visual inspection
4.8 Drooping characteristic
4.9 Flat characteristic
4.10 Welding circuit
4.11 Welding current
4.12 Load voltage
4.13 No-load voltage
4.14 Conventional value
4.15 Conventional welding condition
4.16 Conventional load
4.17 Conventional welding current (l2)
4.18 Conventional load voltage (U2)
4.19 Rated value
4.20 Rating
4.21 Rated maximum welding current (l2max)
4.22 Rated minimum welding current (l2min)
4.23 Rated no-load voltage (Uo)
4.24 Unreduced rated no-load voltage
4.25 Rated supply voltage (U1)
4.26 Rated supply current (l1)
4.27 Rated maximum supply current (l1max)
4.28 Rated load speed
4.29 Rated maximum no-load speed
4.30 Duty cycle; duty factor (X)
4.31 Clearance
4.32 Creepage distance
4.33 Pollution
4.34 Pollution degree 1
4.35 Pollution degree 2
4.36 Pollution degree 3
4.37 Pollution degree 4
4.38 Micro-environment
4.39 Material group
4.40 Temperature rise
4.41 Thermal equilibrium
4.42 Thermal protection
4.43 Thermal detector
4.44 Thermal protector
4.45 Environment with increased hazard of electric
       shock
4.46 Hazard reducing device
4.47 Voltage reducing device
4.48 Switching device from a.c. to d.c.
4.49 Protection Class I equipment
4.50 Protection Class II equipment
4.51 Basic insulation
4.52 Supplementary insulation
4.53 Double insulation
4.54 Reinforced insulation
Section two. Requirements and tests
5. Test conditions
5.1 Type tests
5.2 Routine tests
6. Protection against electric shock
6.1 Insulation
6.1.1 Clearances and creepage distances
6.1.2 Insulation resistance
6.1.3 Dielectric strength
6.2 Protection against electric shock in normal
       service (direct contact)
6.2.1 Degree of protection of the enclosure
6.2.2 Capacitors
6.3 Protection against electric shock in case of
       a fault condition (indirect contact)
6.3.1 Isolation of input and welding circuit
6.3.2 Insulation between input and welding circuit
6.3.3 Placing of internal conductors
6.3.4 Movable coils and cores
7. Thermal rating
7.1 Heating test
7.1.1 Tolerance of the load voltage
7.1.2 Duration of the heating test
7.2 Methods of temperature measurement
7.2.1 Thermometer method
7.2.2 Resistance method
7.2.3 Determination of the ambient air temperature
7.2.4 Measurement of temperatures of parts of the
         welding power source
7.3 Limits of temperature rise
7.3.1 Windings, commutators and slip-rings
7.3.2 External surfaces
7.4 Power rectifier assembly
7.5 Commutators and slip-rings
8. Thermal protection
8.1 Construction of thermal protection
8.2 Location
8.3 Operation
8.4 Resetting
8.5 Operating capacity
8.6 Indication
9. Connection to the main supply
9.1 Range of supply voltage
9.2 Power supply
9.3 Means of connection
9.4 Terminals
9.4.1 Connection at the terminals
9.4.2 Construction of the terminals
9.4.3 Fixing of the terminals
9.4.4 Input conductor terminals
9.4.5 Protective-conductor terminal
9.5 Cable Anchorage
9.6 Inlet openings
10. Output
10.1 Rated no-load voltage
10.1.1 Rated no-load voltage for use in environments
         with increased hazard of electric shock
10.1.2 Rated no-load voltage for use in environments
         without increased hazard of electric shock
10.1.3 Rated no-load voltage for the use with
         mechanically held torches with increased
         protection for the operator
10.1.4 Rated no-load voltage for special processes
10.2 Type test values of the conventional load
       voltage
10.2.1 Manual metal arc welding with covered
         electrodes
10.2.2 TIG welding
10.2.3 MIG/MAG welding
10.2.4 Submerged arc welding
10.3 Operating under load
10.4 Welding output connection
10.4.1 Protection against unintentional contact
10.4.2 Location of socket outlets
10.4.3 Outlet openings
10.4.4 Three-phase multi-operator welding transformer
10.4.5 Marking of d.c. polarity
10.5 Power supply to external devices
10.6 Combined use
11. Auxiliary and control circuits
12. Hazard reducing device
12.1 Voltage reducing device
12.2 Switching device from a.c. to d.c.
12.3 Connection of a hazard reducing device
12.4 Interference with operation of a hazard
       reducing device
12.5 Operating time
12.6 Indication of satisfactory operation
12.7 Fail to a safe condition
12.8 Position for satisfactory operation
13. Mechanical requirements
13.1 Impact resistance
13.2 Lifting means
13.3 Drop withstand
13.4 Tilting stability
14. Rating plate
14.1 Description
14.2 Contents
14.3 Tolerances
15. Indication of current or voltage control
16. Instructions for use
Annex
2A. Normative references
Tables
I Minimum clearances and creepage distances for
     basic insulation and supplementary insulation
II Dielectric test voltages
III Minimum distance through insulation
IV Temperature limits
V Range of conductor dimensions to be accepted by
     the power supply terminals
VI Pull and torque
VII Summary of allowable rated no-load voltages
Figures
1. Measurement of peak values
2. Impact hammer
3. Principle of the rating plate
4. Example of a rating plate: single-phase
     transformer
5. Example of a rating plate: rotating frequency
     converter
6. Example of a subdivided rating plate.

Safety requirements for the construction and relevant performance requirements and test methods for compliance of power sources for arc welding and allied processes designed for industrial and professional use and supplied by a voltage within the low voltage range or driven by mechanical means.