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Talking about the optimization design of explosion-proof motor structure

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The structure of explosion-proof motor

Compared with ordinary motors, the biggest feature of explosion-proof motors is that the junction box, base, end cover, junction box bottom and cover of the explosion-proof motor are provided with isolation surfaces on their joint surfaces.The setting of these isolation surfaces is no different from that of ordinary motors, except that explosion-proof motors have relatively high requirements on sealing. When designing an explosion-proof motor, in order to improve the sealing performance of the explosion-proof motor, not only the matching area is increased, but also the matching precision between various components is increased. A series of sealing measures such as adding rubber gaskets and applying sealant are adopted in the design of these parts with enlarged mating areas. When sealing the explosion-proof motor, the most important thing is to strictly seal and isolate the junction box of the explosion-proof motor from the inside of the casing, so that it can not only meet the requirements of the explosion-proof motor to isolate dust, but also meet the waterproof use standard. Explosion-proof motors have relatively high requirements on the materials used inside. When designing explosion-proof motors, junction boxes, end caps and bases must be made of materials with high strength, so as to ensure the stability of the internal structure of explosion-proof motors and avoid parts and components. The quality of the motor is not up to standard and the internal pressure of the motor is too large to cause an explosion, which will burst the casing of the explosion-proof motor. When selecting materials for explosion-proof motor parts, it is not only necessary to strictly guard the quality of the materials, but also to carry out pressure resistance tests on the selected parts. After passing the test, these parts can be assembled into explosion-proof motors.

Classification of explosion-proof motors

According to the principle of motor, explosion-proof motors can be classified into explosion-proof synchronous motors, explosion-proof asynchronous motors and explosion-proof DC motors. If it is divided according to the principle of explosion-proof, it can be divided into dust explosion-proof motor, positive pressure motor, explosion-proof motor, increased safety motor and non-sparking motor

  1. The shell of the dust explosion-proof motor has strong sealing performance, which can effectively prevent or less enter the shell, and even if there is dust entering, it cannot reach the level of ignition.
  2. The homogeneous system of the positive pressure motor is relatively complete and has a higher mechanical strength. The casing and pipes are made of non-combustible materials, and can maintain a sufficient positive pressure relative to the outside atmosphere.
  3. The explosion-proof motors are all made of B-grade heating assessment and F-grade insulating materials. The grade of the protective casing meets the standard requirements of IP55, and the deep groove ball bearings with low noise are selected. The heat sink of the motor has radiation. There are two forms of distribution and parallel horizontal distribution.
  4. The increased safety motor adopts a brushless excitation system. Such a system has accurate excitation, stable performance, no impact, and the layout design of the entire circuit is very reasonable. Therefore, the discharge resistor will not heat up during operation, and the excitation current also remain within the controllable range.
  5. The non-sparking motor will not ignite the explosive mixture in the surrounding environment under normal production conditions, and there will be no ignition failure under normal circumstances.

Repair of motor fans and fan covers

The explosion-proof motor has strong working stability and can be widely adapted to various harsh working environments. The explosion-proof motor can work continuously and stably. The importance of the cooling fan is self-evident. Since the cooling fan is always working, in general, the explosion-proof motor fan has a high durability and a long service life, but it may also be affected by various factors, which may cause problems. Once the fan of the explosion-proof motor fails, effective repair methods should be implemented in time to quickly eliminate the problem. During maintenance, when encountering relatively tight parts or external hoods, a safety distance of at least 1mm must be maintained. Otherwise, friction damage will be easily caused during the maintenance process, and serious fire will be caused. Once the fan of the explosion-proof motor is damaged or seriously aged, the fan of the motor needs to be replaced in time. In the process of replacement, it is necessary to pay attention to the explosion-proof inspection of the replaced parts, and also to inspect the quality and performance of the replaced parts, so as to ensure that the explosion-proof motor can continue to operate normally and safely.

Explosion-proof motor flameproof housing repair

During the use of the explosion-proof motor, sometimes small cracks appear on the explosion-proof casing. Therefore, once such a phenomenon occurs, the explosion-proof casing needs to be replaced in time. Because the quality of the explosion-proof casing determines the performance of the explosion-proof motor to a certain extent, the source of the problem must be found out when the replaced explosion-proof casing is returned to the factory for maintenance. If the quality of the explosion-proof casing of the explosion-proof motor does not meet the relevant national use standards, then once the situation occurs, it is easy to cause a safety accident when the explosion-proof motor is running. In this case, it will not only affect the normal operation of other equipment, but also Serious threat to the safety of life and property of the staff. Therefore, once the quality problem of the flameproof casing is found, it must be repaired and replaced in time.

Repair of explosion -proof motor wiring boxes

The junction box is also an important component inside the explosion-proof motor. When the junction box fails, the segments in the box will be burned and damaged. When replacing electronics, be sure to pay attention to the type and specification of the terminal, because the terminal is a relatively close component, and there are many types of explosion-proof motors in the current market in my country, so when replacing the terminal, you must strictly follow the damaged terminal type. to replace. In the process of replacement, the industry standards must be strictly implemented to introduce different devices to repair the terminals according to the maintenance requirements, so as to ensure the working performance and quality of the explosion-proof motor.

Optimization analysis of explosion-proof motor structure

Explosion-proof motor shaft sealing structure

The key point for the protection level of the explosion-proof motor to reach IP65 is the sealing design at the penetration of the motor shaft. At present, most of the seal designs on the market use the labyrinth loop structure. This structure needs to maintain a clearance distance of 0.2 mm in the radial direction and 0.5 mm in the axial direction. Design knots have relatively high requirements for assembly, and the processing is more difficult, so there are many restrictions in various aspects. To address this limitation, we optimized the motor seal structure. We can use the static characteristics of the skeleton oil seal and the rotation characteristics of the shaft surface oil seal to make a combined design to form a secondary labyrinth structure between them, the shaft and the end cover, so that the explosion-proof motor can be completely prevented from dust. When dust enters, it can meet the protection requirements of IP65, which is not affected by low-pressure jets at any angle. Such a combined design not only has lower requirements for shaft play, but also has good practical performance.

Structural Improvement Design of Explosion-Proof Motor

The main reason for the failure of the junction box is the overheating of the motor. If the failure of the junction box cannot be dealt with in time during the operation of the motor, the junction box will collapse and burn. Therefore, to solve this problem, it is necessary to optimize the existing structure of the junction box to reduce the failure of the junction box caused by the overheating of the motor. When carrying out structural optimization design, we can appropriately increase the cavity gap between the junction box and the terminal, so as to ensure that the core wire of the cable is crimped, so as to avoid overheating of the junction box. When we carry out the structural optimization design, we must analyze the causes of frequent failures, find the problem of the failure, and then optimize and adjust the internal structure and layout of the explosion-proof motor in a targeted manner. When we optimize the design of the junction box, we also carry out scientific and reasonable compensation and optimization work for its existing defects and loopholes. When carrying out the structural optimization design work, we must take into account the overall layout, and consider the local structure based on the overall layout.

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