General concepts related to turbine generator insulation materials used in rotor windings

This paper provides a general overview of the thermal, mechanical and electrical properties of insulation materials used to create durable turbine generator rotor windings. Discussions will include some key concepts related to the material selection and material performance of common insulation components in rotor windings. Common industry testing methods to measure or specify material properties will be reviewed in this paper... The author will include discussions on material properties in relation to the typical service conditions for Class F (TI 155) rotor winding insulation materials. There are two basic types of Siemens Energy rotor winding designs that will be considered in this paper. The two types of rotor windings considered in this paper are ldquoloosely wedgedrdquo rotor slot contents and ldquotightly wedgedrdquo rotor slot contents. These designs originate from Westinghouse and Siemens AG technologies. These designs use air or hydrogen cooling gas in the windings. The author will identify common rotor winding insulation materials in the Introduction section with detailed discussions of each insulation component in later sections.