Arrangement for detecting and locating the positions of insulation faults in the heating rods of points heating systems, has means for applying an impulse voltage between the heating output lines and earth

摘要

Arrangement comprises a resistance measurement arrangement with which it is detected if the measured resistance of rods falls below a minimum value. If this occurs an impulse voltage is applied between the heating output lines (4) and earth. A test current is if formed which varies between minimum and maximum values. An isolation resistance is formed for each heating rod and compared with a parameter minimum value.