Table of Contents

1 Overview
  1.1 Scope
2 References
3 Insulation test specimens
4 Test procedures
  4.1 Initial screening tests
  4.2 Temperature aging
  4.3 Mechanical stress
  4.4 Thermal shock
  4.5 Moisture exposure
  4.6 Dielectric proof test
5 Interpretation of data
  5.1 Criteria of failure
  5.2 Method of determining average life
  5.3 Extrapolation of data
  5.4 Application of results
  5.5 Report of results
Annex A (informative) Bibliography

Abstract

Establishes a uniform method by which the thermal endurance of of electrical insulation systems for dry-type speciality and general-purpose transformers can be compared. These systems are meant for use in the types of transformers found in NEMA ST 1-1998 and NEMA ST 20-1992. Generally these dry-type transformers are used with primary windings connected to secondary distribution circuits of 600 V nominal and below.

General Product Information

Published
Document Type	Standard
Status	Current
Publisher	Institute of Electrical & Electronics Engineers
Pages
ISBN
Supersedes	IEEE DRAFT 259 : D8 NOV 91