| 摘要 |
PURPOSE:To reduce accidents due to lightning surge voltage, by providing discharge electrodes at tip parts of elastic conductors, which have one ends fixed to input terminals of a watthour meter and are parallel with each other, to absorb a lightning surge voltage in the input terminal side of the watthour meter. CONSTITUTION:Elastic conductors 10 have one ends fixed to input terminals 1 and 2 in the power source side of a watthour meter, which is fitted to an insulating base 9, in parallel with each other by tightening screws 12, and discharge electrodes 11 face to each other at tip parts of elastic conductors 10 with a gap interposed and are fixed by welding. An insulating spacer 13 is inserted near discharge electrodes 11 between elastic conductors 10 to hold a discharge gap length. If a lightning surge higher than the protection level invades between input terminals 1 and 2, the gap between discharge electrodes 11 is discharged to limit the lightning surge voltage to a level lower than the protection level, and an electromangetic repulsive force acts upon elastic conductors 10 by a dynamic current accompanied with discharging to increase the gap length between discharge electrodes 11, thus cutting off the lightning surge. As the result, the dielectric breakdown in the indoor load side, the electric shock, and the occurrence of a fire are prevented. |
