IEEE 792-1988 pdf free.IEEE Trial-Use Recommended Practicefor the Evaluation of the Impulse VoltageCapability of Insulation Systems for AC Electric Machinery EmployingForm-Wound Stator Coils.
IEEE 792 It is recognized that there areseveral aging factors that can affect the life ofan electrical insulation system in a rotatingmachine. Those aging factors are temperature，electrical stress,environmental (ambient) conditions,and mechanical stress.Thesefour factors are discussed in great detail inIEC 505-1975 [8].5
The best understood of these factors is theeffect of temperature. The thermal limitationsof electrical insulation are described inANSIIEEE Std 1-1986 [1 ] and ANSI/EEE Std99-1980 [3]. There have been several IEEE testprocedures on comparative thermal evaluation of rotating machine insulation based onthese two publications.
The thermal test procedure for ac form wound coils is ANSI/IEEE Std 275-1981[4].Forpurposes of maintaining consistency in IEEEdocuments，ANSI/IEEEStd 275-1981 [4] has test procedure. Itshould benoteermaal nife isevaluated and only thermal effects are accelerated. The other three factors (electrical, am-bient,mechanical) are used as diagnostics todetect thermal degradation.
Another reference onthermal aging isANSI/IEEE Std 429-1972 [5].The second best understood aging factor iselectrical stress.1EC 727-1982 [10], is a description of some of the aspects of electricalaging.
IEC505-1975 [8] recognizes that more thanone of the aging factors might be acceleratedin the evaluation of an insulation system. IEC792-1984,[11], is a description of some of theaspects of multifactor testing. IEC610-1978[6],deals with the subject of assessing the insulation to determine if detrimental aging hasoccurred. In order to assess the insulationcondition，it is usually necessary to makesome other type of diagnostic test, eg mechanical stress or electrical stress. Inaddition,these diagnostic tests can be used in combination to determine the condition of the insulation.This procedure is a multifactor aging testcombining thermal aging and electrical aging. For comparison and indication of interactions of the two accelerated factors, the pro-cedure includes testing two other equivalentgroups of samples,each with only one of thetwo aging factors, voltage with no temperature(ie，room temperature) and temperature without voltage.The effects of ambient conditionsand mechanical stresses are not used as agingfactors in this test procedure. However,a mechanical vibration is applied prior to break-down of the specimens，which indicateswhether or not the mechanical properties of theinsulation have deteriorated to the extent thatthe vibration produces disintegration, thus reducing voltage strength to some arbitrarybreakdown level. In the case of this procedure,the mechanical vibration is not intended as anaging factor as a function of time, but is ap-plied to help seek out electricalthermal deterioration prior to breakdown. In this case, themechanical vibration is only a diagnostictool.IEEE 792 pdf download.