| 摘要 |
PURPOSE: To surely prevent the electrostatic charging and spark discharge in an equipment for electrostatic countermeasure for preventing the generation of an electrostatic spark discharge in a dangerous atmosphere by covering a place where static electricity is easily discharged in an object with a material having a specified electric resistance. CONSTITUTION: A place where static electricity is easily discharged (e.g. a protecting frame 22) of an object (e.g. a luminaire 20) is covered with a material having an electric resistance R (Ω) shown by the expression 2T/C.1n 2Wc/ CE<2> )-1}<R<1.0×10<12> . In the expression, Wc is the electrostatic energy (J) in the critical state where a speak discharge is generate, (c) is the electrostatic capacity (F) of a charged body, E is the charged potential (V) of the charged body, and T is the discharging time (sec).
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