An enameled wire with a semi-conductive layer: A solution for a better distibution of the voltage stresses in motor windings

Abstract

The paper analyzes a possible improvement of Pulse Width Modulation (PWM) fed motor insulation according to a principle developed by the high voltages industry. The proposed principle consists in using a specific enameled wire made with an additional semi-conductive layer on its outer surface. Experimental study is realized in order to measure Partial Discharges (PDs) activity with three technologies: Classical enameled wire, enameled wire with an external conductive layer (silver paint) and enameled wire with an external semi-conductive layer (2% of carbon nanoparticles). Simulations are made in order to understand the behavior of the new semi-conductive wire.

Pressure scaling laws for partial discharges in wedge-shaped, dielectric-bounded gas gaps

“…This has been observed to lower the PDIV below a certain threshold frequency [19]. In sufficiently humid atmospheres (≳100 gm −3 in [21,22]), the PDIV has been observed to increase again, possibly due to the formation of a connected conductive film which allows charge transport not only on the dielectric layers but also in between them, thus enabling a screening of the electric field in the air gap [23]. Such effects are not included in the present model.…”