Explosion-proof motor is a kind of motor that can be used in flammable and explosive factories, and does not generate electric spark during operation.
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Explosion-proof motors are mainly used in coal, oil and gas, petrochemical and chemical industries. In addition, it is widely used in textile, metallurgy, city gas, transportation, grain and oil processing, paper, medicine and other departments. Explosion-proof motors are used as the main power equipment and are commonly used to drive pumps, fans, compressors and other transmission machinery.
With the development of science and technology and production, the places where there is a danger of explosion are also increasing. For example, edible oil production used to be a traditional pressing process. After the 1970s, China began to introduce advanced foreign leaching oil processes. However, chemical solvents containing hexane were used in this process. Hexane is flammable and explosive. Substance; therefore, the leaching oil plant becomes a dangerous place for explosions, requiring the use of explosion-proof motors and other explosion-proof electrical products. In another example, in recent years, China's highways have developed rapidly, and a large number of fuel gas stations have emerged, which has also provided a new market for explosion-proof motors.
Product Categories
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 coal mines and explosion-proof motors for factories.
3. According to the principle of explosion-proof, it can be divided into explosion-proof type motor, increased safety type motor, positive pressure type motor, non-sparking type motor and dust explosion-proof motor.
4. According to the matching main machine, it can be divided into explosion-proof motor for coal mine transport machine, explosion-proof motor for coal mine winch, explosion-proof motor for rock loader, explosion-proof motor for local fan of coal mine, explosion-proof motor for valve, explosion-proof motor for fan, marine explosion-proof motor, Heavy-duty brushless excitation synchronous motors for heavy metallurgical explosion-proof motors and hydrogenation units. In addition, it can also be divided according to technical indexes such as rated voltage and efficiency, such as high-voltage 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 principle of explosion protection.
Product series and its characteristics
1. The blackout type motor uses a flameproof enclosure to separate electrical parts that may generate sparks, arcs, and hazardous temperatures from the surrounding explosive gas mixture. However, the outer casing is not sealed, and the surrounding explosive gas mixture can enter the interior of the motor through the gaps of the various parts of the outer casing. Explosion may occur when it comes into contact with an ignition source such as a spark, an arc, or a dangerous high temperature in the casing. At this time, the flameproof casing of the motor is not damaged or deformed, and when an explosion flame or hot gas is transmitted through the gap of the joint surface, It also does not 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 complies with GB3836.1-83 "General requirements for explosion-proof electrical equipment for explosive atmospheres" and GB3836.2-83 "Explosion-proof electrical equipment for explosion-proof electrical equipment "d","; motor power range is O. 55-200kW, the corresponding frame number range is 80-315nun for the center of the machine base; the explosion-proof marks are dI, dIIAT4, dIIBT4, which are applicable to the underground mine fixed equipment or factory IIA, IIB, and the temperature group is T1. - T4 group of flammable gases or explosive mixtures of air and air; the main body enclosure is IP44, can also be made IP%4, junction box protection class IP54; rated frequency is 50Hz, rated voltage is 380, 1660, 1140, 380/660, 660/140V; motor insulation grade is F grade, but the temperature rise of stator winding is evaluated according to grade B, which has a large temperature rise margin. The main models of the low-voltage flameproof three-phase asynchronous motor derivative series are: YB series (dIIcT4) (the center height of the base is 80-315mm), YBSO series (low power, the center height of the base is 63-90mm), YBF series ( For fans, the center height of the base is 63-160mm), YB-H series (for ships, the center height of the base is 80~280mm), YB series (medium, the center height of the base is 355-450mm), YBK series (for coal mines) , the center height of the base is 100-315mm), YB-W, B-TH, YB-WTH series (the center height of the base is 80-315mm), YBDF-WF series (for outdoor anti-corrosion explosion-proof electric valves, the base The center height is 80-315mm) and the YBDC series (explosion-proof capacitor-start single-phase asynchronous motor, the center height of the base is 71-100mm) and the YBZS series of explosion-proof two-speed three-phase asynchronous motors. In addition, there are YB series high-voltage flameproof three-phase asynchronous motors (the center height of the machine base is 355~450mm, 560-710mm). The YB2 series jointly designed by the industry has passed the national appraisal at the end of 1st, 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 15 frame numbers (the center height of the frame is 63, 355nmm), and the power range is O. 12-315kW.
Its main features are:
(1) The correspondence between power class, installation size and speed is consistent with DIN42673. Considering the compatibility with the YB series and the interchangeability of the Y2 series, necessary adjustments are made, which 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 is lower than that of the YB series, which is close to the Y-class noise of the YB series, and the vibration limit is equivalent to the YB series.
(4) The enclosure protection level is increased to IP55.
(5) The whole series uses low-noise deep groove ball bearings, and the center of the machine base is higher than 180mm.
(6) There are two types of motor heat sinks: parallel horizontal distribution and radiation distribution, which are mainly parallel horizontal distribution.
(7) The main performance indicators reached the international advanced level in the early 1990s.
2. Increased safety motor It is a motor structure that does not generate arc, spark or dangerous high temperature under normal operating conditions, and then takes some mechanical, electrical and thermal protection measures to further avoid normal or approved overload conditions. There is a risk of arcing, sparking or high temperatures to ensure its explosion-proof safety.
The basic series of low voltage increased safety of the current application is YA series increased safety three-phase asynchronous motor, it is the Y series (IP44) three-phase asynchronous motor derivative products. Explosion-proof performance meets the requirements of GB3836.1-83 "General requirements for explosion-proof electrical equipment for explosive atmospheres" and GB3836.3-83 "Enhanced-type electrical equipment for explosion-proof electrical equipment "e""; the power range is O. 55~90kW, the corresponding center height of the base is 80-280mm; the explosion-proof marks are eIITl, eIIT2, eIIT3, which are applicable to the place with explosive mixture of temperature group Tl-T3 and slightly corrosive medium in the factory; The protection level of the outer casing is IP54, the protection degree of the junction box is IP55; the rated frequency is 50Hz, the rated voltage is 380V; the motor adopts Class F insulation.
The main models of the low-voltage increase-safety motor derivative series are: YASO series small power increased safety three-phase asynchronous motor (the center height of the machine base is 56-90mm), YA-W, YA-WFl series outdoor, indoor anti-corrosion increased safety type Three-phase asynchronous motor (the center height of the base is 80-280mm).
At present, the joint design work of the YA2 series has been completed, and trial production is being organized to replace the YA series. The YA2 full range of 15 machine bases (the center height of the base is 63-355mm), the power range is 0.12-400kW, which will enable China's increased safety motors to reach the international advanced level of similar products in the 1980s.
High-voltage (6kV) increased safety three-phase asynchronous motor series: YA355-450, power 160-450kW; YA560-900, power 500-1800kW; YAm355-630 water-cooled, power 220-2500kw; YAKK355~630 air-air cooling, power 185-2000kW. The TAKW4000-20/2600, 4000kW increased safety brushless excitation synchronous motor produced in trial production in 1999 is a new explosion-proof motor developed to meet the needs of oil refinery oil deep processing hydrogenation unit.
Its characteristics are:
(1) To meet the requirements of increased safety explosion-proof motors, a series of reliable measures to prevent sparks, arcs and dangerous high temperatures can be safely operated in explosion hazardous areas in Zone 2.
(2) Using brushless excitation, setting the rotating rectifying plate and static excitation cabinet, the excitation control system is reliable; the ac directional slip is accurate and has no impact; the excitation system is out of step protection and reliable, and the whole step ability is strong; the circuit design is reasonable. The discharge resistor does not generate heat during operation; the excitation current adjustment range is wide.
(3) Synchronous machine, AC exciter and rotating rectification coil are coaxial. The rectifier 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 adopted, and the temperature rise is evaluated according to Class B.
(6) Changing the traditional lower water cooling to the upper water cooling, that is, the water cooler is placed on the upper part of the motor.
(7) An increased-type anti-moisture heater is installed 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 calculations to meet the operational reliability and temperature requirements of increased safety motors.
(9) There are perfect monitoring measures; the increased safety-type self-balancing current transformer for differential protection is installed in the main junction box; the stator winding is buried and the standby platinum thermal resistance is set, the graduation number is Pt100; The instrument monitors the leakage of the water cooler; the sliding bearing at both ends is provided with an on-site temperature display instrument and a remote signal terminal.
3. Positive pressure type motor is a kind of positive pressure type electrical equipment.
Its structural characteristics are:
(1) There is a complete ventilation system, and there is no structural dead angle inside the motor that may affect the ventilation.
(2) The outer casing and piping are made of non-combustible material and have sufficient mechanical strength.
(3) The casing and the main pipe maintain a sufficiently large positive pressure relative to the outside atmosphere.
(4) The motor must have safety protection devices (such as time relay and flow monitor) to ensure sufficient air exchange, and must also have automatic protection or alarm device for air pressure under pressure in the casing.
(5) The quick opening door or cover on the outer casing shall have means for interlocking with the power supply. There is no unified series of positive pressure motors in China.
5. Non-sparking type motor: A motor that does not ignite the surrounding explosive mixture under normal operating conditions and generally does not ignite. Compared with the increased safety motor, except for the insulation dielectric strength test voltage, winding temperature rise, te (the AC winding after reaching the rated operating final temperature at the highest ambient temperature, from the start of the starting current to the rise to the limit The time of the temperature) and the starting current are not the same as those of the increased safety type, and the other aspects are the same as those of the increased safety type.
The non-sparking type motor complies with the provisions of GB3836.1-83 and GB3836.8-87 "Explosion-proof electrical equipment for non-sparking electrical equipment "n". The design pays attention to the sealing measures of the motor. The protection of the main body is IP54 and IP55, and the junction box is IP55. For motors rated above 660V, the connection of the space heater or other auxiliary equipment shall be placed in a separate junction box.
At present, YW series non-sparking motor products have been developed and produced in China (the height of the center of the machine base is 80~315mm). The explosion-proof mark is nIIT3, which is suitable for the 2 zone where the factory contains a flammable gas with a temperature group of T1—T3 or an explosive mixture of steam and air. The rated frequency is 50Hz, the rated voltage is 380, 660, 380/ 660V. The motor adopts F insulation, but the temperature rise limit of the stator winding is evaluated according to the B grade, which has a large temperature rise margin and high safety and reliability. The power is 0.55~200kW.
6. Dust explosion-proof motor: It is designed and manufactured according to the specified conditions. It can prevent dust from entering the motor casing or can not completely prevent the dust from entering. However, the amount of entry does not hinder the safe operation of the motor, and the accumulation of internal dust is not easy to cause ignition danger. It also does not cause a motor to explode around an explosive dust mixture. Its characteristics are:
(1) The outer casing has a high degree of sealing to reduce or prevent dust from entering the outer casing, and even if it enters, its intrusion does not pose a risk of ignition.
(2) The maximum surface of the control enclosure is allowed to not exceed the specified temperature group. Currently, it has been used in mechanized equipment for the national grain reserve. The national standard for dust explosion-proof electrical equipment is GBl2476.1-90 "Explosive-proof electrical equipment for explosive dust environment".
development trend
1. Mine explosion-proof motor
(1) Development of high-power motors: At present, the largest installed capacity of shearers in the world has exceeded 1200kw, and its drive motor power reaches 600kW; the corresponding mining area working surface #p#page title#e# scraper conveyor maximum installed capacity The capacity has exceeded 1500kW, and its drive motor power has reached 725kW. The current maximum power of the shearer drive motor in China is 400kW, and the maximum power of the scraper conveyor drive motor is 315kW.
(2) Development of mining motors with 3.3kV, 6kV and IOkV voltages: this is because the length of the mining area after the popularization of integrated mechanized coal mining units is lengthened, resulting in an increase in voltage drop, and the use of high-power motors also requires an increase in voltage levels. .
(3) Development of two-speed motor for mining: In order to meet the needs of low-speed starting and high-speed operation of coal mine conveyors, foreign mining scraper conveyors are driven by two-speed motors. However, the power range, performance index and performance of the supporting control switch of the domestic mine two-speed motor have a certain gap compared with the foreign advanced level.
(4) Improve the reliability of mining machinery: the working condition of mine explosion-proof motor is poor, the motor frequently starts with large load, the load changes greatly, the voltage fluctuation is large, the ambient temperature is high and there is certain corrosiveness, etc. Reliability and life of the motor.
(5) Speed ​​up the replacement of mine explosion-proof motors.
(6) Standard for unifying explosion-proof motors for mines.
2. Explosion-proof motor for petrochemical system
(1) Demand for increased safety and non-sparking motors will increase. Users of petrochemical systems are in use; they have recognized the need to develop China's increased safety and non-sparking motors. In addition, a large number of 1970s bows [increased safety-type, non-sparking motors in the installations have now been replaced with appropriate national products.
(2) The reliability of explosion-proof motors has been increasingly concerned by petrochemical system users. The development of petrochemical enterprises is becoming more and more large-scale and continuous in operation, requiring system operation to achieve long-term, maintenance-free or less maintenance. Therefore, explosion-proof motors have become the key equipment to ensure the above requirements.
(3) Explosion-proof and high-efficiency variable frequency speed-regulating motors have become energy-saving products that petrochemical users are urgently required to develop. In recent years, YBx and YAX explosion-proof high-efficiency motors have been produced in series, which are very popular among users after they are put on the market. Explosion-proof motor energy saving has two aspects: first, to develop high-efficiency explosion-proof motor products, and second, to develop a large number of special products for various explosion-proof speed-regulating motors, especially to design motors for fans, pumps and compressors with great energy-saving potential as Speed ​​motor.
(4) New requirements brought about by the development of coastal petrochemical enterprises. A number of refineries will be built along the coast of China, and crude oil needs to be imported. Imported crude oil has high sulfur content and serious corrosiveness. Therefore, explosion-proof motors are required to improve anti-corrosion performance. In addition, imported crude oil needs to be shipped by sea, and its storage tanks need high matching. Explosion-proof motor for lift large flow oil pump.
(5) The great development of the western petroleum industry in China requires the development of explosion-proof motor products suitable for dry and hot desert environments. The market demand for medium and large capacity increased safety brushless excitation synchronous motors for hydrogenation units will increase year by year.
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