This is a series of videos of Nishisan tips conducted by the NISHI company. The GAP-N electrical tests will be presented by Ivan Massao from Nishi’s Marketing and Engineer Fábio Toshio from Predictive Engineering. In this series we will make demonstrative and explanatory videos about the main tests for diagnosis and evaluation of medium and high voltage motors and generators. In this video we present the surge test. In the video we perform a practical demonstration to identify insulation failure between windings and a simulation with insulation resistance test on a coil with insulation failure between windings.