交流低電圧特殊回路火花のメタン着火限界
炭鉱防爆機器の本質安全回路に関する研究 (第1報)
1973 年 89 巻 1027 号 p. 599-604
詳細
1973 年 89 巻 1027 号 p. 599-604
Tests were conducted to study the minimum currents to ignite methane by electricsparks generated at the voltages lower than 100V in AC circuits. Three types of spark generator were used in the tests.
The minimum igniting current at a fixed voltage depends on the self-inductance of the transformer used in the circuit, and the current indicated somewhat decreasing tendency with decreasing self-inductance. The spark generators of both German and English type showed better performances than hand-operating type, and the least igniting currents were obtained by German type at lower voltages than 10V, and by English type at higher voltages than 10V. When an electrostatic capacitance of about 100PF is connected in parallel to the inductance in the load circuit, the minimum igniting current decreases with increase of inductance.
When electric sparks are generated by repeating on-off operation of either line of the resistances connected in parallel in AC circuit, the lower resistance is easier to ignite methane.
