IEEE - The Institute of Electrical and Electronics Engineers@ Inc.
Scope
This standard gives principles for the development of test procedures to evaluate the thermal endurance of solid electrical insulating materials in air. The results of accelerated thermal endurance tests@ which are conducted according to prescribed procedures@ shall be used to establish temperature indexes (TIs) for insulating materials. Thermal endurance tests and TIs can be used to provide relative comparisons between the thermal capability of new materials and older@ more established materials.TIs@ while giving guidance on materials@ should not in themselves be taken to predict the relationship between temperature and life of an insulation material in service.Thermal endurance tests provide a means for determining the rate at which important properties of insulating materials deteriorate irreversibly as a function of temperature and time. Such tests and the TIs derived from them can aid in selecting insulating materials for use in electrical equipment operating under a wide variety of service conditions.The test procedures covered by this standard apply to solid insulating materials@ including processed compositions of raw materials@ before they are fabricated into insulating structures identified with specific parts of electric equipment.Tests for specific types of insulating materials@ such as wire enamel@ varnish@ sheet@ tape@ etc.@ are not within the scope of this standard; procedures should be developed for each specific type.The mechanical@ chemical@ and electrical properties of the materials when new should be evaluated separately by test methods not within the scope of thermal endurance test procedures. The properties so determined may indicate that one or more@ or combinations of these@ will be the limiting factor in a particular application rather than thermal endurance.These procedures may not apply to the aging characteristics of dielectric fluids or of porous materials impregnated with dielectric fluids.A distinction between material tests and tests to evaluate the performance of insulation systems is necessary because the details of the particular use of a material may not be known to its manufacturer.NOTE??General principles for designating the thermal capability of insulating systems are given in IEEE Std 1-2000? [B4]1. See also IEEE Std 99-1980? [B5] and IEC 60611-1978 [B2].