How to determine whether the motor is explosion-pr

2022-09-22
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How to determine whether the motor is explosion-proof

1 Explosion proof motors are generally used in flammable and explosive places

2. The sealing of the junction box of explosion-proof motor is better than that of ordinary motor

3. The lowest protection grade of explosion-proof motor is IP55, while ordinary motors range from ipip23, IP44, IP54, IP55, IP56, so it can be distinguished from the appearance

the following describes the explosion-proof motor in detail:

the explosion-proof motor is a kind of motor that can be used in flammable and explosive plants, and does not produce electric sparks during operation. Explosion proof motors are mainly used in coal mines, oil and gas, petrochemical and chemical industries. In addition, it is also widely used in textile, metallurgy, urban gas, transportation, grain and oil processing, papermaking, medicine and other departments. As the main power equipment, explosion-proof motor is usually used to drive pumps, fans, compressors and other transmission machinery

with the development of technology and production, the number of places with explosion hazards is also increasing. For example, the production of edible oil used to use the traditional pressing process. After the 1970s, China began to introduce foreign advanced oil extraction process, but in this process, chemical solvents containing hexane, which is flammable and explosive, should be used; Therefore, the oil extraction workshop has become an explosion-proof place, requiring the use of explosion-proof motors and other explosion-proof electrical products. For another example, in recent years, China's roads have developed rapidly, and a large number of fuel gas stations have appeared, which also provides a new market for explosion-proof motors

product classification

1 According to the principle of motor, it can be divided into explosion-proof asynchronous motor, explosion-proof synchronous motor and explosion-proof DC motor

2. According to the place of use, it can be divided into explosion-proof motors for underground coal mines and explosion-proof motors for factories

3. According to the explosion-proof principle, it can be divided into explosion-proof motor, increased safety motor, positive pressure motor, non sparking motor and dust explosion-proof motor

4. According to the supporting host, it can be divided into explosion-proof motor for coal mine conveyor, explosion-proof motor for coal mine winch, explosion-proof motor for rock loader, explosion-proof motor for coal mine local fan, explosion-proof motor for valve, explosion-proof motor for fan, marine explosion-proof motor, explosion-proof motor for hoisting metallurgy and increased safety brushless excitation synchronous motor for hydrogenation device. In addition, it can also be divided according to the rated voltage, efficiency and other technical indicators, such as high-voltage explosion-proof motor, high efficiency explosion-proof motor, high slip explosion-proof motor and high starting torque explosion-proof motor. This paper introduces the classification according to the explosion-proof principle

product series and its characteristics

1 Flameproof motors

adopt flameproof enclosures to separate the electrical parts that may produce sparks, arcs and dangerous temperatures from the surrounding explosive gas mixture. However, the enclosure is not sealed, and the surrounding explosive gas mixture can enter the motor through the gap between the joint surfaces of various parts of the enclosure. Explosion may occur when it comes into contact with spark, arc, dangerous high temperature and other ignition sources in the housing. At this time, the flameproof housing of the motor will not be damaged or deformed, and when the explosion flame or hot gas is sent out through the gap of the joint surface, it cannot ignite the surrounding explosive gas mixture

the basic series of low-voltage flameproof motor products widely used in China is Yb series flameproof three-phase asynchronous motor, which is a derivative of Y Series (IP44) three-phase asynchronous motor. Explosion proof performance conforms to gb3836 General requirements for explosion proof electrical equipment for explosive atmospheres and gb3836 "Explosion proof electrical equipment for explosive atmospheres, explosion proof electrical equipment" d ", regulations; The motor power range is 0.55 ~ 200kW, and the corresponding frame number range is that the center height of the frame is 80 ~ 315nun; The explosion-proof signs are di, diiat4 and diibt4, which are respectively applicable to underground fixed equipment in coal mines or places with explosive mixture formed by combustible gas or steam and air in factory class IIa and IIB and temperature group T1 ~ T4; The protection grade of the main housing is IP44, which can also be made into ip%4, and the protection grade of the junction box is IP54; The rated frequency is 50Hz, and the rated voltage is 380, 1660, 1140, 380/660, 660/140v; The insulation grade of the motor is grade F, but the temperature rise of the stator winding is assessed according to grade B, which has a large temperature rise margin. The main models of the derivative series of low-voltage explosion-proof three-phase asynchronous motors are: Yb series (diict4) (the height of the center of the base is 80 ~ 315mm), ybso series (small power, the height of the center of the base is 63 ~ 90mm), YBF series (for fans, the height of the center of the base is 63 ~ 160mm), yb-h series (for ships, the height of the center of the base is 80 ~ 280mm), Yb series (medium, the height of the center of the base is 355 ~ 450mm), Ybk series (for coal mines, the height of the center of the base is 100 ~ 315mm), yb-w, b-th, yb-wth series (the height of the center of the base is 80 ~ 315mm), ybdf-wf series (for outdoor anti-corrosion and explosion-proof electric valves, the height of the center of the base is 80 ~ 315mm), ybdc series (explosion-proof capacitor starting single-phase asynchronous motor, the height of the center of the base is 71 ~ 100mm) and YBZS series hoisting explosion-proof two speed three-phase asynchronous motor. In addition, there are Yb series high-voltage explosion-proof three-phase asynchronous motors (the center height of the base is 355 ~ 450mm, 560 ~ 710mm). The YB2 series jointly designed by the industry has passed the national appraisal at the end of 2014, and will gradually replace the Yb series and become the basic series of explosion-proof three-phase asynchronous motors in China. YB2 series has 15 base numbers (the center height of the base is 63, 355nmm), and the power range is o.12 ~ 315KW

its main features are:

(1) the corresponding relationship between power level, installation size and speed is consistent with din42673. At the same time, considering the inheritance with Yb series and the interchangeability with Y2 series, necessary adjustments have been made to make it more effective and applicable

(2) the whole series adopts class F insulation, and the temperature rise is assessed according to class B

(3) the noise limit is lower than that of Yb series, close to the level I noise of Yb series, and the vibration limit is equivalent to that of Yb series

(4) the protection grade of the housing is increased to IP55

(5) the whole series adopts low-noise deep groove ball bearings, and the motor with the center height of the base above 180mm is equipped with an oil injection and drainage device

(6) there are two kinds of motor heat sinks: parallel horizontal distribution and radiation distribution, mainly parallel horizontal distribution

(7) the main performance indicators reached the international advanced level in the early 1990s

2. Increased safety motor

is a motor structure that will not produce arc, spark or dangerous high temperature under normal operating conditions, and then take some mechanical, electrical and thermal protection measures to further avoid the danger of arc, spark or high temperature under normal or recognized overload conditions, so as to ensure its explosion-proof safety

the basic series of low-voltage increased safety type currently applied in China is Ya series increased safety three-phase asynchronous motor, which is a derivative of Y Series (IP44) three-phase asynchronous motor. Explosion proof performance conforms to gb3836 General requirements for explosion proof electrical equipment for explosive atmospheres and gb3836 Provisions of "explosion proof electrical equipment for explosive atmospheres increased safety electrical equipment" e "; The power range is 0.55 ~ 90kw, and the corresponding base center height is 80 ~ 280mm; The explosion-proof signs are eiitl, eiit2 and eiit3, which are respectively applicable to places in the factory with explosive mixtures with temperature groups of TL ~ T3 and slightly corrosive media; The protection grade of the main housing is IP54, and the protection grade of the junction box is IP55; The rated frequency is 50Hz and the rated voltage is 380V; The motor adopts class F insulation

the main models of the derivative series of low-voltage increased safety motors are: yaso series low-power increased safety three-phase asynchronous motors (the height of the base center is 56 ~ 90mm), ya-w and Ya WFL series outdoor and indoor anti-corrosion increased safety three-phase asynchronous motors (the height of the base center is 80 ~ 280mm)

at present, China has completed the industry joint design of YA2 series and is organizing trial production to replace Ya series. The YA2 full series has 15 frame numbers (the height of the frame center is 63 ~ 355mm) and the power range is 0.12 ~ 400KW, which will make China's increased safety motor reach the advanced level of similar products in the world in the 1980s

high voltage (6kV) increased safety three-phase asynchronous motor series: Ya, power 160 ~ 450KW; Ya, power 500 ~ 1800kW; Yam water cooling, power 220 ~ 2500kw; Yakk355 ~ 630 air-air cooling, power 185 ~ 2000kW. The takw/2600, 4000kW increased safety brushless excitation synchronous motor, which was trial produced in 1999, is a new explosion-proof motor developed to meet the needs of oil deep processing hydrogenation unit in refinery

its characteristics are:

(1) meet the requirements of increased safety explosion-proof motor, and take a series of reliable measures to prevent sparks, arcs and dangerous high temperatures, which can safely operate in zone 2 explosion hazardous places

(2) brushless excitation is adopted, rotating rectifier panel and static excitation cabinet are set, and the excitation control system is reliable; The excitation of forward polarity slip is accurate without impact; The excitation system has reliable out of step protection and strong re step ability; The circuit design is reasonable, and the discharge resistance does not heat during operation; Wide regulation range of excitation current

(3) synchronous machine, AC exciter and rotating rectifier plate are coaxial. The rectifier panel is located between the main motor and the exciter, or outside the bearing pedestal

(4) the enclosure protection grade is IP54

(5) class F insulation is adopted, and the temperature rise is assessed according to class B

(6) change the traditional water cooling to upper water cooling, that is, the water cooler is placed on the upper part of the motor

(7) an increased safety moisture-proof heater is set and fixed in the cover at the bottom of the motor for heating and moisture-proof during shutdown

(8) select high-quality raw materials, and leave a large margin for electrical and mechanical calculation, which can meet the temperature requirements of operational reliability and increased safety motors

(9) set up perfect monitoring measures; The increased safety self balancing current transformer for differential protection is set in the main junction box; The working and standby platinum thermistors are embedded in the stator winding, and the graduation number is PT100; Set a water leakage monitor to monitor the leakage of the water cooler; The pedestal type sliding bearings at both ends are respectively equipped with on-site temperature display instruments and remote signal terminals

3. Positive pressure motor is a kind of positive pressure electrical equipment. Its structural characteristics are:

(1) it is equipped with a complete ventilation system, and there is no structural dead corner inside the motor that may affect ventilation

(2) the shell and pipe are made of non combustible materials and have sufficient mechanical strength

(3) maintain sufficient positive pressure in the shell and main pipe relative to the outside atmosphere

(4) the motor must be equipped with safety protection devices (such as time relay and flow monitor) to ensure sufficient air exchange capacity, and must also be equipped with automatic protection or alarm device for under pressure of air pressure in the shell

(5) the quick opening door or cover on the shell must have a device interlocked with the power supply. At present, there is no unified positive pressure motor series in China

4. Non sparking motor

refers to a motor that will not ignite the surrounding explosive mixture under normal operating conditions, and generally will not cause ignition failure. Compared with the increased safety motor, the design requirements of the increased safety motor are the same except that there are special provisions on the insulation dielectric strength test voltage, winding temperature rise, te (the time from the start of passing the starting current to the limit temperature of the AC winding after reaching the rated final operating temperature at the highest ambient temperature) and the starting current ratio

non sparking motor conforms to gb3836 And gb3836 Provisions of "explosion proof electrical equipment for explosive atmospheres non sparking electrical equipment" n ". The design pays attention to the sealing measures of the motor. The protection grade of the main housing is IP54 and IP55, and the junction box is IP55. Space heater or other auxiliary devices for motors with rated voltage above 660V

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