Investigations on dielectric properties of enameled wires with nanofilled varnish for rotating machines fed by inverters

The dielectric and mechanical properties of standard (PEI), nanoscale-filled and microscale-filled varnishes are detailed and analyzed in this communication. Fumed silica (10 nm and 400 nm) have been tested as a filler. A particular attention has been paid to partial discharge inception voltage, lifetime under pulse voltage and bonding strength which are crucial for varnish to be used in rotating machines fed by inverters.