Explosion-proof motor status and development trend

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, city gas, transportation, grain and oil processing, papermaking, medicine and other departments. Explosion-proof motors, as the main power equipment, are usually used to drive pumps, fans, compressors and other transmission machinery.
With the development of science and technology and production, there are also places where there is danger of explosion. For example, in the past, the production of edible oil was performed using the traditional crushing process. After the 970s, China began to introduce advanced oil extraction technology from abroad. However, in this process, chemical solvents containing hexane are used. Hexane is flammable and explosive. Substance; therefore, the oil leaching workshop has become a dangerous place for explosion, requiring the use of explosion-proof motors and other explosion-proof electrical products. Another example is the rapid development of highways in China in recent years, and the emergence of a large number of fuel gas stations has also provided a new market for explosion-proof motors.
Product Classification . According to the principle of motor can be divided into explosion-proof asynchronous motor, explosion-proof synchronous motor and explosion-proof DC motor. 2. According to the location of use, it can be divided into explosion-proof motors for coal mines and explosion-proof motors for factories. 3. According to the principle of explosion-proof can be divided into explosion-proof motor, increased safety motor, positive pressure type motor, non-spark type motor and dust explosion-proof motor. 4. According to the matching host machine can be divided into explosion-proof motor for coal transporter, explosion-proof motor for coal mine winch, explosion-proof motor for rock loader, explosion-proof motor for coal mine fan, explosion-proof motor for valve, explosion-proof motor for fan, explosion-proof motor for ship , hoisting metallurgical explosion-proof motor and hydrogenation device supporting increased safety brushless excitation synchronous motor. In addition, according to the rated voltage, efficiency and other technical indicators can be divided, such as high-pressure explosion-proof motor, high-efficiency explosion-proof motor, high slip rate explosion-proof motor and high starting torque explosion-proof motor. This article is classified according to the explosion-proof principle.
Product Series and Features
. Exclusion type motors It uses a flameproof enclosure to isolate electrical parts that may generate 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 interior of the motor through the interface gaps of the various parts of the enclosure. Explosion may occur when in contact with ignition sources such as sparks, arcs, dangerous high temperatures, etc. in the enclosure. In this case, the flameproof enclosure of the motor will not only not be damaged or deformed, but also the explosion flame or hot gas will be emitted through the gap of the joint surface. Nor can it ignite the surrounding explosive gas mixture.
The basic series of low-voltage flameproof motor products that are widely used in China are YB series explosion-proof three-phase asynchronous motors. It is a derivative product of Y series (IP44) three-phase asynchronous motors. Explosion-proof performance in line with GB3836.-83 "General requirements for explosion-proof electrical equipment for explosive environment" and GB3836.2-83 "Explosion-proof electrical equipment explosion-proof electrical equipment "d", "" provisions; motor power range is O. 55-200kW, corresponding frame size range is 80-35nun center height; explosion-proof mark is dI, dIIAT4, dIIBT4, applicable to the coal mine underground fixed equipment or factory IIA, IIB level, temperature group is T - Location of explosive mixture of flammable gas or vapor and air in T4 group; protection class of main body enclosure is IP44, also can be made into IP%4, protection class of junction box is IP54; rated frequency is 50Hz, rated voltage is 380, 660, 40, 380/660, 660/40V; Motor insulation class F, but according to class B assessment of stator winding temperature rise, with a large temperature margin.
The main types of low-voltage explosion-proof three-phase asynchronous motor derived series are: YB series (dIIcT4) (center height is 80-35mm), YBSO series (low power, center height is 63-90mm), YBF series ( For wind turbines, the base height is 63-60mm), YB-H series (for ships, base height is 80-280mm), YB series (medium-sized, base height is 355-450mm), YBK series (for coal mining , Base height is 00-35mm), YB-W, B-TH, YB-WTH series (base height is 80-35mm), YBDF-WF series (for outdoor anti-corrosion flameproof electric valve, frame The center height is 80-35mm) and YBDC series (explosion-proof capacitor-start single-phase asynchronous motor, base height is 7-00mm) and YBZS series explosion-proof two-phase three-phase asynchronous motor for lifting. In addition, there are YB series high-voltage explosion-proof three-phase asynchronous motor (frame height is 355 ~ 450mm, 560-70mm).
The YB2 series jointly designed by the industry passed the national appraisal at the end of 4th and will gradually replace the YB series, becoming the basic series of flameproof three-phase asynchronous motors in China. The YB2 series has a total of 5 frame sizes (the center height of the frame is 63, 355 nm), and the power range is O.2-35 kW. Its main features are: () The correspondence relationship between power level, installation size, and rotation speed is consistent with DIN42673. Taking into account the inheritance of the YB series and the interchangeability of the Y2 series, necessary adjustments have been made and are 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 value is lower than that of the YB series, and it is close to the I-class noise of the YB series. The vibration limit is equivalent to the YB series. (4) The degree of protection of the enclosure is increased to IP55. (5) Low-noise deep-groove ball bearings are used in the entire series, and the motor center is set at 80 mm or more for the oil discharge device. (6) Motor cooling fins have parallel horizontal distribution and radiation distribution, mainly parallel horizontal distribution. (7) The main performance indicators reached the international advanced level in the early 990s.
2. Increased safety type motor It is a motor structure that will not generate arc, spark or dangerous high temperature under normal operating conditions, and then take some mechanical, electrical and thermal protection measures to further avoid normal or recognized overload conditions. There is a danger of arcs, sparks or high temperatures underneath, thus ensuring its explosion-proof safety.
The basic series of low-voltage increased safety currently used in China is the YA series increased safety three-phase asynchronous motor, which is a derivative of the Y series (IP44) three-phase asynchronous motor. Explosion-proof performance meets the requirements of GB3836.-83 "General requirements for explosion-proof electrical equipment for explosive atmosphere" and GB3836.3-83 "Extended electrical equipment for explosion-proof electrical equipment "e""; power range is O.55~ 90kW, corresponding to the center height of the stand 80-280mm; explosion-proof signs for eIITl, eIIT2, eIIT3, are applicable to factories with temperature groups Tl-T3 group explosive mixture and a place with slight corrosive medium; The protection class is IP54, the protection level of the junction box is IP55, the rated frequency is 50Hz, the rated voltage is 380V, and the motor adopts class F insulation.
The main types of the low-voltage increase safety motor derivative series are: YASO series low-power increase safety type three-phase asynchronous motor (frame height is 56-90mm), YA-W, YA-WFl series outdoor, indoor anti-corrosion increase safety type Three-phase asynchronous motor (frame height is 80-280mm).
At present, YA2 and series of industrial joint design work have been completed, and trial production is being organized to replace the YA series. YA2 full range of a total of 5 frame number (frame center height is 63-355mm), power range of 0.2-400kW, will enable China's increased safety motor to reach the international advanced level of similar products in the 980s.
High-voltage (6kV) increased safety three-phase asynchronous motor series: YA355-450, power 60-450kW; YA560-900, power 500-800kW; YAm355-630 water cooling, power 220-2500kw; YAKK355-630 air-cooled, power 85-2000kW. TAKW4000—20/2600, 4000kW increased-safety brushless excitation synchronous motors that were trial-produced in 999 are new types of explosion-proof motors that are developed to meet the needs of refinery oil deep-processing hydrogenation units.
Its characteristics are: () to meet the requirements of increased safety explosion-proof motor, take a series of reliable measures to prevent sparks, arcs and dangerous high temperature, can safely operate in the explosion hazardous areas in Zone 2. (2) Adopt brushless excitation, set the rotary rectifier plate and static excitation cabinet, the excitation control system is reliable; the polarity deviation and the excitation are accurate, no impact; the excitation system is out of step protection is reliable, and then the whole step ability is strong; the circuit design is reasonable The discharge resistor does not generate heat during operation; the excitation current regulation range is wide. (3) Synchronous machine, AC exciter and rotating rectifier plate coaxial. The commutator disk is located between the main motor and the exciter, or outside the housing. (4) The enclosure protection class is IP54. (5) Class F insulation is used, and temperature rise is assessed according to Class B. (6) Change the traditional water cooling to the upper water cooling, that is, the water cooler is placed on the upper part of the motor. (7) An increased-safety type moisture-proof heater is fixed in the hood at the bottom of the motor and is used for heating and moisture-proof at the time of shutdown. (8) Select high-quality raw materials, electrical and mechanical calculations to leave a larger margin, to meet the operating reliability and increased safety requirements of the temperature of the motor. (9) Complete monitoring measures are provided; Increased-safety self-balancing current transformers for differential protection are installed in the main terminal box; Pt thermal resistances for stator winding work and spares are provided; the index number is Pt00; The instrument monitors the leakage of the water cooler; the two-piece seated sliding bearings are equipped with on-site temperature display instruments and remote signal terminals, respectively.
3. Positive pressure type motor is a type of positive pressure electrical equipment. Its structural features are: () It is equipped with a complete set of ventilation system, and there is no dead space in the motor that may affect ventilation. (2) The housing and the pipe are made of non-combustible material and have sufficient mechanical strength. (3) The housing and the main pipe maintain a sufficiently large positive pressure with respect to the outside atmosphere. (4) The motor must have safety protection devices (such as time relays and flow monitors) to ensure sufficient ventilation, and must also have automatic protection or alarm devices with under-pressure in the housing. (5) The quick opening door or cover on the housing shall have means for interlocking with the power supply.
There is no unified positive pressure motor series in China.
4 no spark type motor
It refers to a motor that does not ignite the surrounding explosive mixture under normal operating conditions, and generally does not cause ignition failure. Compared with the increased safety type motor, except for the insulation dielectric strength test voltage, winding temperature rise, te (ac winding after reaching the rated operating final temperature at the highest ambient temperature, from the start of the passage of the starting current to the rise to the limit The time of temperature and the starting current ratio are not the same as those of the increased safety type, and other aspects are the same as those of the increased safety type. The non-spark type motor complies with the provisions of GB3836.-83 and GB3836.8-87 "Explosion-proof electrical equipment without explosion-type electrical equipment "n"". The design emphasizes the sealing measures of the motor, the main enclosure protection class is IP54, IP55, and the junction box is IP55. For motors with rated voltage above 660V, the connection of space heaters or other auxiliary devices shall be placed in a separate junction box. At present, YW series non-spark type motor products have been developed and produced in China (the height of the machine base is 80~35mm). The explosion-proof mark is nIIT3 and is applicable to the Zone 2 area where the factory contains explosive mixtures of flammable gases or vapors and air with temperature groups of T to T3. The rated frequency is 50Hz, the rated voltage is 380, 660, 380/660V, and the motor adopts F insulation. However, the temperature rise limit of the stator winding is evaluated according to Class B, which has large temperature margin and high safety and reliability. The power is 0.55~200kW. 5. Dust explosion-proof motor refers to its shell designed and manufactured according to the specified conditions, can prevent dust from entering the motor casing or can not completely prevent dust from entering, but the amount of its entry does not prevent the motor from running safely, and the internal dust accumulation is not easy to produce ignition hazard. At the same time it will not cause the explosion of the surrounding explosive dust mixture motor. Its characteristics are: () The enclosure has a high degree of tightness to reduce or prevent dust from entering the enclosure. Even if it enters, the amount of its entry will not create a risk of ignition. (2) The maximum surface allowable temperature of the control enclosure does not exceed the specified temperature group. At present, it has been used in the mechanized equipment of the national grain reserve bank. The national standard for dust explosion-proof electrical equipment is GBl2476.-90 "Explosion-proof electrical equipment for explosive dust environments".
development trend
Mine explosion-proof motor
() Development of high-power motors: At present, the world's largest installed capacity of coal mining machines has exceeded 200kw, and its drive motor power has reached 600kW; the maximum installed capacity of the scraper conveyor in the mining area's working face has exceeded 500kW. The motor power has reached 725kW. The current domestic maximum power of the shearer drive motor is 400kW, and the maximum power of the scraper conveyor drive motor is 35kW. (2) Development of mining motors with 3.3kV, 6kV, and IOkV class voltages: This is because the adoption of integrated mechanized coal mining units will lead to a longer mining area, leading to an increase in voltage drop. At the same time, the use of high-power motors also requires higher voltage levels. (3) Development of mining two-speed motors: In order to adapt to the low-speed start-up and high-speed operation of coal conveyors, foreign mining scraper conveyors are driven by two-speed motors. However, at present, the power range, performance indicators and the performance of supporting control switches of domestic two-speed mines have certain gaps compared with the advanced level in foreign countries. (4) Improve the reliability of mine motor: Mine explosion-proof motor has poor working conditions, frequent heavy load start of motor, large load change, large voltage fluctuation, high ambient temperature and certain corrosiveness, etc. The reliability and life of the motor. (5) Accelerate the upgrading of mining explosion-proof motors. (6) Standard for mine explosion-proof motors.
2. Explosion-proof motor for petrochemical system
() The demand for increased safety and non-sparking motors will increase. Users of petrochemical systems are using the practice; they have realized the necessity of developing safe and non-sparking motors in China. In addition, a large number of increased-safety, spark-free motors in the 970s were now available when appropriate national products were substituted. (2) The reliability of explosion-proof motors has been increasingly concerned by petrochemical system users. The development of petrochemical enterprises is increasingly becoming large-scale and continuous in operation. It requires system operation to achieve long-term, maintenance-free or less maintenance. Therefore, the explosion-proof motor has become the key equipment to ensure the above requirements. (3) Explosion-proof and high-efficiency frequency-conversion speed-regulating motors have become energy-saving products that petrochemical users urgently require to develop. In recent years, YBx and YAX explosion-proof high-efficiency motors have been produced in series and are welcomed by users after being put into the market. Explosion-proof motor energy conservation has two aspects: one is to develop high-efficiency explosion-proof motor products, and the second is to develop a large number of special products for explosion-proof and speed-regulating motors, especially to design motors with fans, pumps and compressors that have huge potential for energy saving. Speed motor. (4) New requirements brought about by the development of coastal petrochemical enterprises. A batch of refineries will be built in the coastal areas of China, and all crude oils need to be imported. However, imported crude oil has high sulfur content and is highly corrosive. Therefore, explosion-proof motors are required to improve corrosion resistance; in addition, imported crude oil is required to be shipped by sea, and its storage tanks need to be equipped with high Head of large flow pump explosion-proof motor. (5) China's Western Petroleum Industry