EN ISO 17657-3:2007

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Physical environment and operating conditions
5 Classification of current sensing coils and
  designation of product
  5.1 Class of current sensing coils
  5.2 Standard values of the conversion coefficient
  5.3 Designation of products
6 Requirements for current sensing coils
  6.1 Current sensing coil and connecting lead
  6.2 Conversion coefficient
  6.3 Measuring accuracy
  6.4 Mechanical strength
  6.5 Setting position error
  6.6 Influence of ambient temperature
  6.7 Thermal property of cover materials
  6.8 Test
7 Test procedures
  7.1 Conversion coefficient
  7.2 Measuring accuracy
  7.3 Mechanical tests
  7.4 Setting position error test
  7.5 Thermal test
  7.6 Contact test
8 Marking
Annex A (informative) Design of current sensing coils
Annex B (informative) Governing parameters of the
                      conversion coefficient
Annex C (informative) Type of current sensing coils and
                      their recommended specification range
Annex D (informative) Frequency response of current sensing
                      coils

ISO 17657-3:2005 specifies current sensing coils of the toroidal-coil type as a current sensor for welding current meters or a welding current measuring system used to monitor the welding current in resistance welding, and is applicable for both current types, i.e. alternating current of 50 Hz or 60 Hz and direct current.