Protective system for portable electrically powered apparatus

US4954922A · kind A · utility

Inventors

• Harry Gaus · Kronberg, DE
• Hagen Gross · Bad Homburg vor der Höhe, DE
• Gunter Schliebs · Darmstadt, DE

Key dates

• Filing date: Sep 30, 1988
• Grant date: Sep 4, 1990
• Expiry date: Sep 30, 2008

Classification

• Technology area (CPC H): Electricity
• CPC primary: H02H5/083
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

In an electrically powered apparatus, particularly a portable apparatus, having a flexible shielded main connection line (50) and an electronic protective device, said protective device is housed in the main connection plug (60) or in an adapter (61) to which the main connection line (50) can be coupled, wherewith said protective device serves as a safety device in the event of leakage of fluid into the apparatus or of current to ground or to protect the user. In order to provide intrinsic protection against damage or defects which may render the protective device itself ineffective, a holding current loop is provided which extends to the protected apparatus (30) via core conductors (21, 23) and shielding (22) of the main connection line, which holding current loop preferably also includes a probe (40, 41) in the protected apparatus, wherewith, when, regardless of the operating state of the protected apparatus (30), the holding current in the holding current loop falls below a lower limit or increases above an upper limit (depending on the type of failure event), the protective device (5-20) is triggered. Means are provided to prevent accidental or willful interposition of an inven…