1. Explosion-proof motors are generally used in flammable and explosive environments. 2. The sealing of the junction box of an explosion-proof motor is better than that of a regular motor. 3. The minimum protection rating of an explosion-proof motor is IP55, while regular motors have ratings of IP23, IP44, IP54, IP55, and IP56, which can be distinguished by their appearance. The following is a detailed introduction to explosion-proof motors: Explosion-proof motors are a type of motor that can be used in flammable and explosive environments and does not produce electrical sparks during operation. Explosion-proof motors are mainly used in coal mines, oil and gas, petrochemical, and chemical industries. In addition, they are widely used in textiles, metallurgy, city gas, transportation, grain and oil processing, papermaking, and pharmaceuticals. As a primary power source, explosion-proof motors are typically used to drive pumps, fans, compressors, and other transmission machinery. With the development of technology and production, the number of locations with explosion hazards is constantly increasing. For example, edible oil production used to rely on traditional pressing methods. After the 1970s, my country began introducing advanced foreign extraction oil technology. However, this process uses chemical solvents containing hexane, which is flammable and explosive. Therefore, extraction oil workshops became hazardous locations, requiring the use of explosion-proof motors and other explosion-proof electrical products. Similarly, the rapid development of highways in my country in recent years has led to a large number of gas stations, creating a new market for explosion-proof motors. Product Classification: 1. By motor principle: Explosion-proof asynchronous motors, explosion-proof synchronous motors, and explosion-proof DC motors, etc. 2. By application location: Explosion-proof motors for underground coal mines and explosion-proof motors for factories. 3. By explosion-proof principle: Flameproof motors, increased safety motors, pressurized motors, sparkless motors, and dust explosion-proof motors, etc. 4. According to the supporting host, explosion-proof motors can be divided into explosion-proof motors for coal mine conveyors, explosion-proof motors for coal mine winches, explosion-proof motors for rock loading machines, explosion-proof motors for local ventilation fans in coal mines, explosion-proof motors for valves, explosion-proof motors for fans, explosion-proof motors for marine applications, explosion-proof motors for hoisting and metallurgy, and increased-safety brushless excitation synchronous motors for hydrogenation units, etc. In addition, they can also be classified according to technical indicators such as rated voltage and efficiency, such as high-voltage explosion-proof motors, high-efficiency explosion-proof motors, high-slip explosion-proof motors, and high-starting-torque explosion-proof motors, etc. This article introduces them according to the explosion-proof principle. [b]Product Series and Characteristics[/b] 1. Extinguishing-proof motors: These use an explosion-proof enclosure to separate electrical parts that may generate sparks, arcs, and dangerous temperatures from the surrounding explosive gas mixture. However, this enclosure is not completely sealed; the surrounding explosive gas mixture can enter the motor through the gaps between the joint surfaces of the enclosure. An explosion may occur when the motor comes into contact with ignition sources such as sparks, electric arcs, or dangerous high temperatures inside the casing. In this case, the explosion-proof casing of the motor will not only remain undamaged or deformed, but the explosion flame or hot gas, when transmitted through the gaps in the joint surfaces, will not ignite the surrounding explosive gas mixture. The basic series of low-voltage explosion-proof motors widely used in my country is the YB series explosion-proof three-phase asynchronous motor, which is a derivative of the Y series (IP44) three-phase asynchronous motor. Its explosion-proof performance complies with the requirements of GB3836.1-83 "General Requirements for Explosion-proof Electrical Equipment for Explosive Atmospheres" and GB3836.2-83 "Explosion-proof Electrical Equipment for Explosive Atmospheres - Flameproof Type 'd'", and the motor power range is 0. 55-200kW, corresponding to frame sizes with a center height of 80-315mm; explosion-proof markings are dI, dIIAT4, and dIIBT4, respectively applicable to fixed equipment in coal mines or factories in IIA and IIB classes, temperature groups T1-T4, for explosive mixtures of flammable gases or vapors with air; the main body enclosure protection rating is IP44, also available as IP40, and the junction box protection rating is IP54; rated frequency is 50Hz, rated voltage is 380, 1660, 1140, 380/660, and 660/140V; the motor insulation class is F, but the stator winding temperature rise is assessed according to Class B, providing a large temperature rise margin. The main models in the low-voltage explosion-proof three-phase asynchronous motor derivative series include: YB series (dIIcT4) (frame center height 80-315mm), YBSO series (small power, frame center height 63-90mm), YBF series (for fans, frame center height 63-160mm), YB-H series (marine, frame center height 80-280mm), YB series (medium size, frame center height 355-450mm), YB... The K series (for coal mines, frame center height 100-315mm), YB-W, B-TH, and YB-WTH series (frame center height 80-315mm), YBDF-WF series (outdoor corrosion-resistant explosion-proof electric valves, frame center height 80-315mm), YBDC series (explosion-proof capacitor-start single-phase asynchronous motors, frame center height 71-100mm), and YBZS series explosion-proof dual-speed three-phase asynchronous motors for hoists. Additionally, there is the YB series high-voltage explosion-proof three-phase asynchronous motor (frame center height 355-450mm, 560-710mm). The YB2 series, jointly designed by the industry, passed national appraisal at the end of 2014 and will gradually replace the YB series, becoming the basic series of explosion-proof three-phase asynchronous motors in my country. The YB2 series has 15 frame sizes (frame center height 63, 355mm), with a power range of 0.12-315kW. Its main features are: (1) The power rating, installation dimensions and speed correspondence are consistent with DIN42673. At the same time, considering the inheritance with YB series and the interchangeability with Y2 series, necessary adjustments have been made, making it more effective and applicable. (2) The entire series adopts F-class insulation, and the temperature rise is assessed according to B-class. (3) The noise limit is lower than that of YB series, close to the I-class noise of YB series, and the vibration limit is comparable to that of YB series. (4) The enclosure protection level is improved to IP55. (5) The entire series uses low-noise deep groove ball bearings, and motors with a frame center height of 180mm or more are equipped with oil injection and drainage devices. (6) There are two types of motor heat sinks: parallel horizontal distribution and radial distribution, with parallel horizontal distribution being the main type. (7) The main performance indicators reach the international advanced level of the early 1990s. 2. Increased safety type motors are motors that, under normal operating conditions, will not produce arcs, sparks, or dangerous high temperatures. Further mechanical, electrical, and thermal protection measures are implemented to further prevent the occurrence of arcs, sparks, or high temperatures under normal or acceptable overload conditions, thus ensuring their explosion-proof safety. The basic series of low-voltage increased safety type motors currently used in my country is the YA series increased safety three-phase asynchronous motor, which is a derivative of the Y series (IP44) three-phase asynchronous motor. Its explosion-proof performance complies with the provisions of GB3836.1-83 "General Requirements for Explosion-Proof Electrical Equipment for Explosive Atmospheres" and GB3836.3-83 "Increased Safety Type Electrical Equipment for Explosive Atmospheres 'e'"; the power range is 0. The motors range from 55 to 90 kW, with corresponding frame center heights of 80 to 280 mm. Explosion-proof markings are eIIT1, eIIT2, and eIIT3, suitable for factories with explosive mixtures of temperature groups T1-T3 and slightly corrosive media. The main casing has an IP54 protection rating, and the junction box has an IP55 protection rating. The rated frequency is 50 Hz, and the rated voltage is 380 V. The motor uses Class F insulation. The main models in the low-voltage increased safety type motor derivative series include: the YASO series small-power increased safety three-phase asynchronous motor (frame center height 56-90 mm), and the YA-W and YA-WF1 series outdoor and indoor corrosion-resistant increased safety three-phase asynchronous motors (frame center height 80-280 mm). Currently, the industry joint design work for the YA2 series has been completed, and trial production is underway to replace the YA series. The YA2 series comprises 15 frame sizes (frame center height 63-355mm), with a power range of 0.12-400kW, bringing my country's increased safety motors to the advanced international level of similar products in the 1980s. The high-voltage (6kV) increased safety three-phase asynchronous motor series includes: YA355-450, power 160-450kW; YA560-900, power 500-1800kW; YAm355-630 water-cooled, power 220-2500kW; YAKK355-630 air-to-air cooled, power 185-2000kW. The TAKW4000-20/2600, 4000kW increased safety brushless synchronous motor, trial-produced in 1999, is a new type of explosion-proof motor developed to meet the needs of petroleum deep processing hydrogenation units in oil refineries. Its features are: (1) It meets the requirements of the increased safety explosion-proof motor, and adopts a series of reliable measures to prevent sparks, electric arcs and dangerous high temperatures, so it can operate safely in Zone 2 explosion-hazardous locations. (2) It adopts brushless excitation, and is equipped with a rotating rectifier and a static excitation cabinet. The excitation control system is reliable; the polarity slip excitation is accurate and without impact; the excitation system has reliable step loss protection and strong re-stepping capability; the circuit design is reasonable, and the discharge resistor does not heat up during operation; the excitation current adjustment range is wide. (3) The synchronous machine, AC exciter and rotating rectifier are coaxial. The rectifier is located between the main motor and the exciter, or outside the bearing housing. (4) The enclosure protection level is IP54. (5) It adopts Class F insulation, and the temperature rise is assessed according to Class B. (6) It changes the traditional bottom water cooling to top water cooling, that is, the water cooler is placed on the top of the motor. (7) It is equipped with an increased safety moisture-proof heater, which is fixed inside the cover at the bottom of the motor for heating and moisture protection when the machine is stopped. (8) Select high-quality raw materials, and leave a large margin in electrical and mechanical calculations to meet the operational reliability and temperature requirements of the increased safety type motor. (9) Set up complete monitoring measures; install an increased safety type self-balancing current transformer for differential protection in the main junction box; embed working and standby platinum resistance thermometers in the stator winding, with a graduation number of Pt100; install a water leakage monitoring instrument to monitor the leakage of the water cooler; install field temperature display instruments and remote signal terminals on the two end seat sliding bearings respectively. 3. Positive pressure type motor is a type of positive pressure type electrical equipment. Its structural characteristics are: (1) It is equipped with a complete ventilation system, and there are no structural dead corners inside the motor that may affect ventilation. (2) The casing and pipes are made of non-combustible materials and have sufficient mechanical strength. (3) The casing and main pipes maintain a sufficiently large positive pressure relative to the outside atmosphere. (4) The motor must have safety protection devices (such as time relays and flow monitors) to ensure sufficient air exchange, and must also have an automatic protection or alarm device for under-pressure of the air inside the casing. (5) The quick-opening door or cover on the casing must have a device interlocked with the power supply. There is currently no unified series of positive pressure type motors in my country. 4. Sparkless motor: refers to a motor that will not ignite the surrounding explosive mixture under normal operating conditions and generally will not experience ignition failure. Compared with the increased safety type motor, except for the insulation dielectric strength test voltage, winding temperature rise, te (the time from the start of the starting current to the limit temperature of the AC winding after reaching the rated final operating temperature at the highest ambient temperature), and starting current ratio, which are not subject to special regulations like those for the increased safety type, the other aspects are the same as the design requirements for the increased safety type motor. Sparkless motors comply with the provisions of GB3836.1-83 and GB3836.8-87 "Explosion-proof electrical equipment for explosive atmospheres - sparkless electrical equipment 'n'". The design emphasizes the sealing measures of the motor, with the main casing protection level being IP54 or IP55, and the junction box being IP55. For motors with a rated voltage of 660V or higher, the connection parts for space heaters or other auxiliary devices should be placed in a separate junction box. Currently, YW series sparkless motors (frame center height 80-315mm) have been developed and produced domestically. The explosion-proof marking is nIIT3, suitable for Zone 2 locations in factories containing explosive mixtures of flammable gases or vapors with air in temperature groups T1-T3. The rated frequency is 50Hz, and the rated voltage is 380, 660, or 380/660V. The motor uses F insulation, but the stator winding temperature rise limit is assessed according to Class B, providing a large temperature rise margin and high safety reliability. The power range is 0.55-200kW. 5. Dust explosion-proof motors: These refer to motors whose casings are designed and manufactured according to specified conditions, capable of preventing dust from entering the motor casing, or although not completely preventing dust from entering, the amount entering does not impede the safe operation of the motor, and the accumulation of dust inside is unlikely to cause an ignition hazard, and will not cause an explosion of the surrounding explosive dust mixture during use. Its characteristics are: (1) The outer shell has high sealing performance to reduce or prevent dust from entering the outer shell. Even if it does enter, the amount of dust entering will not cause an ignition hazard. (2) The maximum allowable surface temperature of the outer shell is controlled to not exceed the specified temperature group. At present, it has been used in the mechanized equipment of the national grain reserve. The national standard for dust explosion-proof electrical equipment is GB12476.1-90 "Explosion-proof electrical equipment for explosive dust atmospheres". Development trend 1. Explosion-proof motors for mining (1) Development of high-power motors: At present, the maximum installed capacity of coal mining machines in the world has exceeded 1200kw, and its drive motor power has reached 600kW; the corresponding maximum installed capacity of scraper conveyors in mining areas has exceeded 1500kW, and its drive motor power has reached 725kW. The maximum power of the drive motor of the coal mining machine in China is 400kW, and the maximum power of the drive motor of the scraper conveyor is 315kW. (2) Develop mining motors with voltage levels of 3.3kV, 6kV and 10kV: This is because the mining area is lengthened after the popularization of integrated mechanized coal mining units, resulting in a larger voltage drop. At the same time, the use of high-power motors also requires higher voltage levels. (3) Develop mining dual-speed motors: In order to adapt to the working needs of low-speed starting and high-speed operation of coal mine conveyors, foreign mining scraper conveyors are all driven by dual-speed motors. However, at present, the power range, performance indicators and the performance of the matching control switches of domestic mining dual-speed motors are all somewhat different from the advanced level abroad. (4) Improve the reliability of mining motors: The working conditions of mining explosion-proof motors are poor. The motors are frequently started under heavy loads, the load changes are large, the voltage fluctuates greatly, the ambient temperature is high and there is a certain degree of corrosion, all of which affect the reliability and lifespan of the motors. (5) Accelerate the upgrading of mining explosion-proof motors. (6) Unify the standards for mining explosion-proof motors. 2. (1) The demand for explosion-proof motors in petrochemical systems (1) Increased safety and spark-free motors will increase. In practice, users in petrochemical systems have realized the necessity of developing increased safety and spark-free motors in my country. In addition, a large number of increased safety and spark-free motors used in advanced equipment in the 1970s are now due for replacement with suitable domestic products. (2) The reliability of explosion-proof motors has become increasingly important to users in petrochemical systems. As petrochemical enterprises develop towards larger and more continuous equipment operation, they require long-cycle, maintenance-free or low-maintenance system operation. Therefore, explosion-proof motors have become key equipment to ensure the above requirements. (3) Explosion-proof and high-efficiency variable frequency speed control motors have become energy-saving products that petrochemical users urgently need to develop. In recent years, YBx and YAX explosion-proof high-efficiency motors have been produced in series and have been well received by users after entering the market. There are two aspects to energy saving in explosion-proof motors: one is to develop high-efficiency explosion-proof motor products, and the other is to develop a large number of special products for various explosion-proof speed-regulating motors, especially to design the motors that are matched with fans, pumps and compressors with huge energy-saving potential as speed-regulating motors. (4) New requirements brought about by the development of coastal petrochemical enterprises. A number of oil refineries will be built along the coast of my country, and crude oil will need to be imported. Imported crude oil has a high sulfur content and is highly corrosive, so explosion-proof motors are required to improve corrosion resistance. In addition, imported crude oil needs to be transported by sea, so its oil storage tanks need to be matched with explosion-proof motors with high head and large flow rate oil pumps. (5) The great development of the petroleum industry in western my country requires the development of explosion-proof motor products suitable for the dry and hot desert environment. The market demand for medium and large capacity brushless excitation synchronous motors with increased safety for hydrogenation units will increase year by year.