Overheating diagnostic manner and its device null of air disconnector contact

摘要

PURPOSE: To accurately diagnose overheat of an air disconnector contact part without relying on experience of an operator after environmental influence is corrected. ;CONSTITUTION: A temperature T of an air disconnector contact part 2 is measured by an infrared ray detector 3, and temperature correction by air speed (v) and a solar radiation quantity W is added, and a corrective measured temperature Ts is obtained. This corrective measured temperature Ts is compared with a reference temperature rising value ΔTA calculated from a carrying electric current I of a measuring object part by a computing element 4, and the existence of overheat is diagnosed. Or temperatures TU, TV and TW of three phases of the air disconnector contact part 2 are measured, and the overheat is similarly diagnosed from a difference between a maximum value and a minimum value.;COPYRIGHT: (C)1996,JPO