Überspannungsschutz für elektrische Geräte

摘要

The device 10 fits over the pins 16, 18 of an electrical power plug 12 and permits normal mating of the plug 12 with a female power supply receptacle. The device may be formed or a monolithic structure with pin-receiving holes 44, 42, and a planar body of varistor material 30 sandwiched between conductive plates 36, 38 having bendable fingers 48, so to contact live and neutral pins of the plug. Three varistor bodies may be included to provide common mode and differential mode protection for equipment having a plug with live, neutral and earth pins (Figs. 6 - 8). Discrete disc type varistors may be used instead of the monolithic structure (Figs. 12 - 14). The device may be secured to an end face of the plug by an adhesive layer (54, Fig. 5). The operational status of the device may be indicated by a lamp (142, Figs. 9 - 11) in series with a fuse (144) rated to burn out at a level well below the maximum current rating of the varistor body.