Explosion - proof motor basic knowledge

China's explosion-proof electrical standards for the motor, the main are:

GB3836.1-2000 "Electrical equipment for explosive gas atmospheres Part 1: General requirements"GB3836.2-2000 "Electrical equipment for explosive gas atmospheres" Part 2: Flameproof type "d" "GB3836.3-2000" Electrical apparatus for explosive gas atmospheres - Part 3: Increased safety type "e" GB / T2900.Electrical technical terminology - Electrical equipment for explosive atmospheres

There are other standards, such as: intrinsically safe "i"; positive pressure "p"; oil-filled "o"; sand "q"; no spark "n"; pouring "m" Explosion-proof and so on.

1.General terms

1.1 Explosion-proof electrical equipment: in the provisions of the conditions will not cause the surrounding explosive atmosphere of electrical equipment.

1.2 Category of electrical equipment for explosive atmospheres: Classes classified as explosive atmospheres used in electrical equipment: Class I: electrical equipment for coal mines; Class II: Electrical equipment for all other explosive gas atmospheres except coal mines.

1.3 Maximum surface temperature: electrical equipment in the specified range of the most unfavorable operating conditions, the surface or any part of the possible and may lead to the surrounding explosive gas environment, the maximum temperature.

1.4 Temperature group: Explosive environment Electrical equipment according to the highest surface temperature of the group.

1.5 Explosive environment: Under atmospheric conditions, the mixture of gas, vapor, mist, dust or fibrous combustible material and air is ignited and burned to the atmosphere of all unburned mixtures.

1.6 Explosive gas environment: At atmospheric conditions, gas, vapor or misty combustible material forms a mixture with air, igniting and burning into the atmosphere of all unburned mixtures.

1.7 Explosive dust environment: Under atmospheric conditions, dust or fibrous combustible material forms a mixture with air, ignited, and burns to an unburned mixture.

1.8 Zone 0 in Hazardous Area Divisions: Areas of continuous or long-term explosive atmospheres.

1.9 Zone 1 in hazardous area division: areas where explosive gas atmospheres may occur during normal operation

1.10 Zone 2 of the Hazardous Area Division: The area where the explosive gas environment is unlikely to occur during normal operation, if present, is only for a short time.

1.11Type tests: tests conducted on one or more electrical equipment manufactured in accordance with a design to determine whether the design complies with the relevant standards.

1.12Routine test: the test of each electrical equipment during manufacture or after completion of manufacture to determine whether it complies with the relevant standards.

1.13 Flameproof enclosure "d": An explosion-proof type of electrical equipment which is capable of withstanding the interior of the flammable mixture that has entered the interior of the enclosure without damage and any joints or structural holes passing through the enclosure are not ignited by one or A variety of gases or vapors formed by the external explosive atmosphere of the electrical equipment shell.

1.14 Increased safety of electrical equipment "e": an explosion - proof type of electrical equipment. It is a kind of electrical equipment that does not produce arcing and sparking electrical equipment under normal operating conditions to take some additional measures to improve its safety and prevent dangerous temperatures, arcs and sparks from occurring inside and outside parts.

1.15 Limiting temperature of electrical equipment for increased safety: Maximum permissible temperature of electrical equipment or its components. It is equal to the lower temperature in the two temperatures determined by the following conditions:

A) Hazardous temperature of ignition of explosive gas atmospheres;

B) Thermal stability of the material used in electrical equipment.

1.16 TE time of the increased electrical equipment: the time required for the AC winding to reach the rated temperature at the maximum ambient temperature from the start of the start current IR until it reaches the limit temperature.

1.17 Operating temperature: The temperature at which the device is at rated operation.

1.18 Enclosure protection class (IP):

The code is preceded by an IP compliant enclosure to indicate the atmosphere

- Prevent personnel from touching the inside of the housing with live parts and moving parts.

- Prevent solids from entering the inside of the device.

- Prevent liquid from immersing inside electrical equipment.

A) 2.Basic knowledge

2.1 use of places

Explosive gas environment with the use of electric motor is divided into:

Class I: Electric motors for coal mines, marked as ExdI.

Class II: In addition to coal mines other than the explosive gas environment with the motor, marked ExdIIAT4, ExdIIBT4, ExdIICT4; in Class II products, IIB motor can replace the IIA motor, IIC motor can replace IIB and IIA motor.

2.2 Temperature

For class I electrical equipment, the maximum surface temperature should not exceed:

- 150 ℃, when the surface of the electrical equipment may accumulate dust;

- 450 ℃, when the electrical equipment surface will not pile up or take measures to prevent the accumulation of dust.

For Class II electrical equipment, the temperature is divided into T1 ~ T6 group, the surface of the highest temperature as follows:

     Class II electrical equipment with the highest surface temperature

2.3 Flameproof three elements is the explosion-proof gap, surface roughness, explosion-proof surface length.

Gap: The distance between the corresponding surfaces of the flameproof joint. For cylindrical surfaces, the gap is a diameter gap (difference between two diameters).

Flame Length: The shortest passage length from the inside of the flameproof enclosure to the outside of the flameproof enclosure.

Among them, the minimum surface roughness of the explosion does not require more than 6.3um