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Classification and main applications of explosion-proof motors 1. Main applications of explosion-proof motors: 1) Explosion-proof motors are generally used in flammable and explosive environments； 2) The sealing of the explosion-proof motor’s wiring box is better than that of ordinary motors ； 3) The protection rating of explosion-proof motors is typically IP55, whereas ordinary motors come in ratings such as IP23, IP44, IP54, IP55, and IP56; thus, they can be distinguished by their appearance ； Explosion-proof motors 2. Classified by product type: 1) Based on the motor principle, they can be divided into explosion-proof asynchronous motors, explosion-proof synchronous motors, and explosion-proof DC motors, etc. 2) Classified by application site, they can be divided into explosion-proof motors for use in coal mines and explosion-proof motors for use in factories. 3) They can be classified into explosion-proof motors, increased-safety motors, positive-pressure motors, spark-free motors, and dust-explosion-proof motors, etc. 4) Classified by the corresponding host machines, they can be divided into explosion-proof motors for coal mine conveyors, explosion-proof motors for coal mine winches, explosion-proof motors for rock loaders, explosion-proof motors for local exhaust fans in coal mines, explosion-proof motors for valves, explosion-proof motors for fans, explosion-proof motors for ships, explosion-proof motors for lifting and metallurgical applications, as well as enhanced safety type brushless excited synchronous motors for use in hydrogenation plants. In addition, they can also be classified based on technical specifications such as rated voltage and efficiency, such as high-voltage explosion-proof motors, high-efficiency explosion-proof motors, explosion-proof motors with high slip rates, and explosion-proof motors with high starting torque. 3. Classified by product series and their characteristics: 1) Flameproof motors use flameproof enclosures to separate the electrical components that may generate sparks, arcs, and dangerous temperatures from the surrounding explosive gas mixture. However, this casing is not sealed, and the surrounding mixture of gases can enter the motor through the gaps at the joints between the various parts of the casing. This can occur when in contact with ignition sources such as sparks, arcs, or dangerous high temperatures inside the enclosure; in such cases, the motor’s flame-proof enclosure not only remains undamaged or deformed, but flames or hot gases escaping through the gaps in the joints also cannot ignite the surrounding flammable gas mixture. The main features of flameproof motors are: (1) The relationships between power, installation dimensions, and speed comply with DIN42673; at the same time, necessary adjustments have been made to take into account compatibility with the YB series as well as interchangeability with the Y2 series, making them more effective and suitable for use. (2) The noise limit is lower than that of the YB series, approaching the I noise level of the YB series, while the vibration limit is comparable to that of the YB series. (3) The entire series uses F rims, with temperature rise evaluated according to standard B. (4) The motor radiators come in two types: parallel horizontal distribution and radial distribution, with the parallel horizontal distribution being the most common. (5) The entire series uses low-noise deep-groove ball bearings, and motors with a frame center height of 180 mm or more are equipped with oil injection and drainage devices. (6) The housing protection level has been increased to IP55. (7) The main performance indicators have reached the advanced level of the early 1990s. 2) Increased safety motors are motor designs that, under normal operating conditions, do not generate arcs, sparks, or dangerous high temperatures; additional mechanical, electrical, and thermal protection measures are then applied to further prevent the occurrence of such hazards under normal or permitted overload conditions, thereby ensuring their explosion-proof safety. Increased safety motors are characterized by the following: (1) They meet the requirements of increased safety explosion-proof motors, incorporating a range of reliable measures to prevent sparks, arcs, and dangerous high temperatures, allowing them to operate safely in Zone 2 hazardous areas. (2) Brushless excitation is used, with a rotating rectifier disc and a static excitation cabinet installed, ensuring reliability of the excitation control system ； The excitation for synchronous droop control is accurate, with no shocks ； The excitation system features reliable out-of-step protection and strong re-synchronization capability ； The circuit design is reasonable, and the discharge resistor does not generate heat during operation ； The excitation current has a wide adjustment range. (3) The synchronous machine, AC exciter, and rotating rectifier disc are coaxial. The rectifier disc is located between the main motor and the exciter, or outside the bearing housing. (4) The enclosure protection level is IP54. (5) Use F edge, and the temperature rise is evaluated according to B. (6) Change from traditional bottom water cooling to top water cooling, that is, the water cooler is placed above the motor. (7) A safety-enhanced moisture-proof heater is installed in the cover at the bottom of the motor, to be used for heating and preventing moisture accumulation when the machine is shut down. (8) High-quality raw materials are selected, with substantial margins in electrical and mechanical calculations to ensure operational reliability and meet the temperature requirements of enhanced-safety motors. (9) Comprehensive monitoring measures are in place ； An intrinsically safe self-balancing current transformer for differential protection is installed in the main wiring box ； Work related to embedding the stator windings and the spare platinum resistance thermometer, with a calibration grade of Pt100 ； Install a leak monitoring device to monitor leaks in the water cooler ； The seated sliding bearings at both ends are equipped with on-site temperature display instruments and remote signal terminals, respectively. 3) Positive-pressure motors are a type of positive-pressure electrical equipment. The structural features of a positive-pressure motor are as follows: (1) It is equipped with a complete ventilation system, and there are no structural dead zones inside the motor that could affect ventilation. (2) The casing and pipes are made of non-combustible materials and possess sufficient mechanical strength. (3) A sufficiently high positive pressure is maintained inside the casing and main pipelines relative to the outside atmosphere. (4) The motor must be equipped with safety protection devices (such as time relays and flow monitors) to ensure an adequate amount of ventilation, and it must also have automatic protection or alarm mechanisms for low pressure inside the casing. (5) The quick-opening door or cover on the enclosure must be equipped with a device that interlocks with the power supply.