SAFETY DEVICE, ELEVATOR SYSTEM, FREQUENCY CONVERSION AND A PROCEDURE FOR MONITORING ELECTRICAL SAFETY IN AN ELEVATOR SYSTEM

摘要

The invention relates to an elevator system and also to a method for monitoring electrical safety in an elevator system. The elevator system comprises a motor drive (1) for driving an elevator car, wherein the elevator system comprises a safety arrangement of an elevator. The safety arrangement comprises the motor drive (1) of the elevator, which motor drive comprises a main circuit (2), an accessible conducting part (3A, 3B, 3C, 3D, 3E), which is earthed, an insulator (4), which is adapted to electrically insulate the aforementioned conducting part (3A, 3B, 3C, 3D, 3E) from the aforementioned main circuit (2) and also a monitoring circuit (6), which is configured to determine an earth fault of the aforementioned main circuit occurring via the aforementioned conducting part (3A, 3B, 3C, 3D, 3E). The monitoring circuit (6) is configured to form a signal indicating the danger of electric shock in the motor drive (1) of the elevator, if the aforementioned earth fault is diagnosed. The safety arrangement comprises a drive prevention apparatus (8, 13) connected to the monitoring circuit (6), which apparatus is configured to remove the elevator from use when an earth fault is diagnosed.