Design criteria for inverter-fed Type 1 motors

According to the IEC 60034-18-41, the reliability of inverter-fed motor electrical insulation must be assessed through qualification tests with stress levels based on empirical assumptions. For purely organic (Type 1) electrical insulation systems, the inception of partial discharges within the insulation systems is the end-life criterion. The aim of this paper is to start a work in the direction of proposing a framework for designing from scratch motor insulation systems with partial discharge inception voltage adequate for inverter applications. To achieve this purpose, inception voltage estimates obtained using streamer inception criteria were compared with measurements performed in the lab. The results show that, for a large class of magnet wires, conservative estimates can be obtained