385 Energy and Power Criterion of Intrinsically Safe Circuits for Explosive Atmospheres

Arc discharge time(T) is determined to be in proportion to time constant(1) based on current linear attenuation model for intrinsically safe inductive circuits. It draws conclusions that maximum value of arc power(⁠P_max⁠) is in proportion to arc energy(⁠W_g⁠) and is inverse to time constant (1).The conflicting fact that greater sparks can not cause gas explosion while the smaller sparks can cause gas explosion is explicated . The arc power criterion of intrinsically safe circuits was established. It argues that the product of maximum value of arc power (⁠P_max⁠) and time constant (1) has a critical value to assessing the intrinsic safety of circuits.