IEEE 259:1999 (R2010)

Revision Standard - Inactive-Reserved.
A uniform method by which the thermal endurance of electrical insulation systems for dry-type specialty and general-purpose transformers can be compared is established. Covered are insulation systems intended for use in the types of transformers described in NEMA ST 1-1988 and NEMA ST 20-1992.

To establish a uniform method for preparing samples, conducting tests, and analyzing results for establishing a comparative thermal life of insulation systems intended for use in dry-type transformers described in NEMA St 1-1988 and NEMA st 20-1992.
To revise the title of this standard to match the scope as stated above. It is also the intent of the WG to make revisions based on recommendations and comments received during balloting so that it will be acceptable as the basis for an international standard.