Sparking electrical discharge and heating in synchronous and induction machines: Can it be controlled?

Abstract

It is impossible to eliminate all occurrences of sparking and localized heating from the interior of electric machines during the 20 to 40 years that they are normally in service. One can minimize the probability of sparking and localized heating by exercising precautions which will eliminate or minimize the sources of these conditions in AC machines. Most new machines have a low probability of sparking but some design steps can be taken which condition the machine as a sparking type or a nonsparking type. The paper discusses the aspects of arcing between rotor and stator in the air gap, sparking between rotor parts, sparking between frame components, sparking due to broken or open bars and endrings, and surface discharge on the stator winding. Also discussed is what action, if any, can be taken in design, application, and maintenance to eliminate or control these problems.designers and users concluded that motors do not spark or arc unless there is an electrical or mechanical failure. IntroductionFIGURE 1. Air gap sparking at locked rotor.

Design, Testing Analysis of High Tension Increased Safety Motor for Hazardous areas

“…Bianco et al [5] investigate the possible incendive effect due to partial discharges in the insulation system. Dymond [4,6] indicated that contamination will lead to surface discharge and tracking on the windings, which is another potential source of sparking and arcing. Hamer et al [7] elaborated on the relationship between hot rotor surfaces and flammable vapor ignition.…”

Design, ignition risk assessment and testing of increased safety high tension induction motor for explosive atmospheres

“…Clark et al [ 5] was concluded the sparking and arcing phenomenon occurs in the air gap at the end pockets of the machines. It was investigated that possible incendive effect because of partial discharges in the insulation system and contamination will lead to surface discharge and tracking on the windings, which is another potential source of sparking and arcing in the motor [7][8][9]. Hamer [10] elaborated on the relationship between hot rotor surfaces and inflammable vapour ignition.…”