IEEE 117:2015 pdf free download

IEEE 117:2015 pdf free download.IEEE Standard Test Procedure for Thermal Evaluation of Systems of lnsulating Materials for Random-wound AC Electric Machinery.
This test procedure has been prcpared to outline useful methods fur the evaluation of systems of insulation for random-wound stators of rotating electric machines, It is expected that the seseral insulating materials, or components making up any insulation system to be tcstcd will first be screened in accordance with specific lest procedures for each type of material. Normally. materials that have given acceptable perforniance in these separate screening tests are be included in the system evaluation tests outlined in this procedure.
This procedure is intended to evaluate insulation systems for use in ‘usual service conditions” with air-cooling. It has also been a useful tool for evaluating systems for specLal requirements where machines arc enclosed in gas atmospheres, subjected to strong chemicals or metal dusts, or submersed in liquids. However, these special requirements are beyond the scope of this test procedure,
4.2 Methods of evaluation
The test procedure includes two principal sections.
a) Clause 5 describes types of specimens to be used for testing as well as recommending a series ofexposures to heat, vibration, and moisture, to which thc specimens Imotorettes) may be subjected to represent cumulative cffccts of long service under accelerated conditioim. Procedures foe applying periodic voltage checks to establish the end point of insulation life .ire also gi cii
b) Clause 6 describes similar procedures when actual motors are used as test specitnens.
Ii is recommended that for each particular system to be evaluated a suitable type of a specimen. natively a motordnc or a complete motor, be selected and then an adequate number of these be subjected to repeated cycles of heat, vibration, moisture, and electrical stress as outlined in 5.2 olihis procedure.
An adequate number of samples to obtain a good statistical average, in no case less than 10 motorefles or five motors, should be carried through the test procedure until failure occurs for each chosen temperature of heat exposure. It is recommended that the tests be carried through on the indicated number of specimens for at least three different test temperatures for each insulation system to be evaluated. To promote uniformity in the results. Table I provides six possible ranges of exposure requiring from 1 d to 32 d per given temperature that are appropriate for making these tcsts.
The number of cycles iiid the total number of hours of heat aging to the end of life for the average of each group of samples and for each of the test temperatures are then reported as the final results of the tests The extrapolated regression line obtained for a new insulation system is determined from these data according to the procedure in IEEE Std 101. The motorette or motor life from an accepted must be used as the criterion to determine the new thermal rating for the insulation system from the plot. A control set of tcst units using an established insulation system should be used so that a comparison of the new system to the old system can be made. As indicated in 5.2.