NBN EN 61858 : 2009

INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 General considerations
5 Evaluation of the change of thickness of an EIM
      5.1 Samples
      5.2 Acceptance
6 Substitution of winding wire
      6.1 General
      6.2 Substitution of enamel
      6.3 Substitution of conductor material
      6.4 Alternate winding wire
7 Substitution of impregnating resin/varnish
      7.1 Thermal class determination
      7.2 Evaluation
             7.2.1 Thermal classes equal or better
             7.2.2 One thermal class lower
             7.2.3 Other criteria
8 Substitution of other EIMs
      8.1 Technically equivalent materials
      8.2 Previous evaluation
      8.3 Other
9 Evaluation of additions
      9.1 Addition of an impregnating resin/varnish
      9.2 Addition of other components
10 Single-point thermal ageing test
      10.1 Test objects
      10.2 Establishing the relative thermal index (RTI)
      10.3 Interpretation of results
Annex A (normative) Classes of winding wire
Annex ZA (normative) Normative references to international
                     publications with their corresponding
                     European publications

Gives the required test procedures for qualification of modifications of an established electrical insulation system (EIS) with respect to its thermal classification.