... in petroleum, metallurgy, chemical industry, electric power, light industry, mechanical and environmental protection and other fields.1 ... in petroleum, metallurgy, chemical industry, electric power, light industry, mechanical and environmental protection and other fields 2 ... resistorcurrent output≥800Ω,7)Insulating resistance≥2000Ω 1000VDC8)Explosion-proof mark: ExdI CT4(flameproof type), Exia CT4( ...