Time： 2021-09-07 11:08:31
1、 Why use explosion-proof motor?
In some places with explosion risk, when the gas or dust meets the fire source or high temperature, it will burn or explode. When the motor is running, arc or electric spark may be generated, which is a strong ignition source. It may explode when encountering explosive dust or gas.
2、 Explosion proof principle of explosion-proof motor
The explosion-proof principle of explosion-proof motor is: put the live parts of the motor in a special shell, which can isolate the spark and arc generated by the electrical parts in the shell from the explosive mixture outside the shell, and can withstand the explosion pressure generated when the explosive mixture entering the shell is detonated by the spark and arc of the electrical equipment in the shell without damaging the shell; At the same time, it can prevent the explosion products in the shell from transmitting to the explosive mixture outside the shell, and will not cause the combustion and explosion of the explosive mixture outside the shell. This special enclosure is called "flameproof enclosure". Motors with flameproof enclosures are called "explosion proof Motors". The mark of explosion-proof motor is "d". In order to realize the flameproof and flameproof performance of flameproof enclosure, there are special requirements for the shape, material, volume and structure of flameproof enclosure.
3、 Classification of explosion-proof motors
Electrical equipment for explosive gas atmospheres can be divided into two categories:
① Electrical equipment for coal mine;
② Electrical equipment for explosive gas atmospheres other than coal mines. Class II electrical equipment can be divided into class II A, class II B and class II C according to the characteristics of explosive gas. The equipment marked with II B can be applied to the service conditions of II a equipment, and the equipment marked with II C can be applied to the service conditions of II A and II B equipment.
4、 Interpretation of several terms
① Explosive environment
Environment where explosion may occur.
② Explosive gas environment
Under atmospheric conditions, the mixture of gas, steam or mist combustible substances and air will burn in the whole unburned mixture environment after being ignited in the mixture.
③ Surface temperature
When the electrical equipment operates under the allowable adverse conditions, the surface or any part of the electrical equipment may reach and ignite the high temperature of the surrounding explosive gas environment.
④ Ignition temperature
The low temperature of a hot surface capable of igniting an explosive gas air mixture.
⑤ High surface temperature
When coal dust may accumulate on the surface of electrical equipment, the high surface temperature shall not exceed 150 ℃.
When the surface of electrical equipment will not accumulate or measures can be taken to prevent coal dust accumulation, the high surface temperature shall not exceed 450 ℃.