通信用誘導線電気火花のメタン着火に関する研究
1971 年 87 巻 995 号 p. 75-78
詳細
1971 年 87 巻 995 号 p. 75-78
The minimum electric power for ignition of fire damp was measured, when the line of the transistor type-Induction Radio was cut off.
The results obtained are as follows
1) For 150Ω of impedance (Z) of the out put transformer, the minimum ignition-power was about 24VA. Therefore, it might be thought that the induction radio with out put of about 5VA actually used in the coal mines is safe for ignition.
2) Connecting the coil to the end of the line, the minimum ignition power was decreased by inductance (L) of the coil and the inductance of 0.04mH lowered ignition power by about 10%. The circuit with the coil (0.04mH), which experimentally resulted in the lowest ignition power, may not be in danger yet at the decrease of about 10% of the ignition power. Otherhand, connecting a transformer in the inductive line, the minimum ignition power was increased in order to the self power loss of the transformer.
3) If we go to use the transistor type induction radio with about 5VA out put in the coal mines, the impedance of the out put transformer in the radio circuit should be lower than 200Ω.
