The concept and principle of explosion-proof motors
Concept of explosion-proof motor
An explosion-proof motor is a kind of motor that can be used in flammable and explosive factories and does not generate electric sparks during operation.
Explosion-proof motors are mainly used in coal mines, oil and gas, petrochemical and chemical industries. In addition, they are also widely used in textile, metallurgy, city gas, transportation, grain and oil processing, papermaking, medicine and other departments. As the main power equipment, explosion-proof motors are usually used to drive pumps, fans, compressors and other transmission machinery.
According to the explosion-proof principle, motors can be divided into flameproof motors/increased safety motors/positive pressure motors/sparkless motors/dust explosion-proof motors.
Basic principles of explosion prevention
(1) Concept of explosion
Explosion is the sudden change of a substance from one state to another through physical or chemical changes, and the release of huge energy. The energy released at a rapid rate will cause the surrounding objects to suffer violent impact and damage. Three conditions must be met for an explosion:
Explosive substances: substances that can react with oxygen (air), including gases, liquids and solids. (Gases: hydrogen, acetylene, methane, etc.; liquids: alcohol, gasoline; solids: dust, fiber dust, etc.
Oxygen: air.
Ignition sources: including open flames, electrical sparks, mechanical sparks, static sparks, high temperatures, chemical reactions, light energy, etc.
(2) Reasons for explosion-proof considerations
Explosive substances: Many production sites produce certain flammable substances. About two-thirds of underground coal mines have explosive substances; in the chemical industry, more than 80% of production workshops have explosive substances.
Oxygen: Oxygen in the air is ubiquitous.
Ignition source: In the production process, electrical instruments are used in large quantities, and various friction sparks, mechanical wear sparks, static sparks, high temperatures, etc. are inevitable, especially when instruments and electrical equipment fail.
Objectively, many industrial sites meet the conditions for explosion. When the concentration of the mixture of explosive substances and oxygen is within the explosion limit, if there is an explosion source, an explosion will occur. Therefore, it is necessary to take explosion-proof measures.