Electrical Atex Motors

The Atex directive

The directive 94/9/EC, known as ATEX (French acronym for ATmosphères EXplosibles) is an European directive defining the health and safety minimum requirements for the equipment which is going to be used in potentially dangerous atmospheres. This directive also allows the products marketing within the EU. The compliance with the essential safety requirements is realized by: 
•The application of sector’s harmonized standards 
• the EC type examination of the product by a notified authority, with the issuing of relative certification; 
•equipment production with a quality management system which has been evaluated and approved by a certified authority

Classification of the explosive atmospheres

The use of electrical equipment in potentially explosive atmospheres due to the presence of mixture of air-fuel gas or air- conductive or combustible dust, must be preceded by a categorization of dangerous areas, to be done in accordance with EN 60079-10 and its related guide.
This specific classification, made by qualified installers, identifies: 
• the equipment group, 
• the category, 
• the protection way, 
• the temperature class or the maximum surface one typical of electric motors to be used in this application

Protection ways

The standard EN 60079-10, classifies the dangerous environments, the EN 60079-14 one, on the other hand, defines the compatibility between dangerous areas and protection ways. The protections ways for the air and gas mixture, steams and fogs, are :
•”d”- flameproof containers (EN 50018)
• "e" – increased security protection way (EN 50019)
• "n" – In accordance with EN 50021 standard
For air and dusts mixture, we’ll have:
• IPy5 + maximum surface temperature (y=6 for 20 category; y=5 for 3D category);
•Electric constructions made for environments with combustible dust (EN 50281-1-1)

Surface maximum temperature

It is the maximum reached temperature on the electrical construction surfaces in worst functional conditions (but within the tolerances according the international Standards). In relation to the potential explosive areas, it’s necessary that the lower temperature of the gas surrounding the equipment, must be higher than the highest surface temperature reachable by the equipment itself