IEEE 1799-2012

This recommended practice provides a procedure to detect external discharges in form-wound bars and coils and complete stator windings of rotating machines operating in air with a rated line-to-line voltage greater than 4200 V at power frequency. The recommended practice is applicable to bars, coils, and complete stator windings. The recommended practice covers two inspection methods: the visual blackout test, and the use of corona imaging instruments.