scope:

Foreword

(This Foreword is not a part of IEEE Std 99-1980, IEEE Recommended Practice for the Preparation of Test Procedures for the Thermal Evaluation of Insulation Systems for Electric Equipment.)

The previous version of IEEE Std 99 was updated and used for guidance in the preparation of IEC (International Electrotechnical Commission) 611 (1978), Guide for the Preparation of Test Procedures for Evaluating the Thermal Endurance of Electrical Insulation Systems. This IEEE recommended practice has now been revised to reflect the changes incorporated in the IEC document. Thus, outside of a few editorial changes, it is substantially the same as IEC 611 (1978) except that IEEE references are used in place of the equivalent IEC references. Any future revisions should be coordinated with IEC 611 (1978) if possible.

This Recommended Practice was prepared by Subcommittee 4.1 of the Standards Coordinating Committee Number 4. At the time it approved this standard, the Standards Coordinating Committee Number 4 had the following membership:

John C. Botts, Chair

Philip E. Alexander

A. C. Baker

E. A. Boulter

E. L. Brancato

R. Brewer

L. W. Brotherton

L. W. Buchanan

G. I. Duncan

Ivan Easton

Howard Feibus

W. J. Foley

E. M. Fort

Niko V. Gjaja

Jack A. Goetz

M. L. Manning

K. N. Mathes

W. B. Penn

Howard E. Reymers

R. G. Rhudy

H. R. Sheppard

W. T. Starr

C. R. Willmore  

Scope

The purpose of this recommended practice is to provide a general form for the preparation of test procedures and to suggest the points to be considered by technical committees in the preparation of specific instructions for the thermal evaluation of insulation systems for equipment. The thermal evaluation of an insulation system involves the thermal (T) factor of influence as described in IEC 505 (1975), Guide for the Evaluation and Identification of Insulation Systems of Electrical Equipment.

These test procedures involve accelerated thermal aging of insulation systems and specify tests which the committees deem pertinent, based on conditions of use. The objective of these test procedures is to provide for the functional evaluation, by test, of insulation systems for electric equipment. The evaluation of insulating materials and simple combinations thereof is provided for by a separate material test guide, IEEE Std 98-1972, Guide for the Preparation of Test Procedures for the Thermal Evaluation and Establishment of Temperature Indexes of Solid Electrical Insulating Materials.

For a detailed discussion of the principles on which IEEE Std 98-1972 and IEEE Std 99-1980 are based, see IEEE Std 1969, General Principles for Temperature Limits in the Rating of Electrical Equipment. Tests based on IEEE Std 98-1972 may be considered as preliminary tests for insulation system evaluation, but should not be used as accepted tests for the classification of systems.