1 Developed on the basis of the DF7G modular locomotive. It is used for trunk transportation in Cuba, with a top speed of 120 km / h, a sustained speed of 18 km / h, and a standard load of 1500. In recent years, it has made important contributions to Cuba's transportation and national economic development. Due to the backwardness of the ancient railways, the ups and downs of the roads, the serious leaks in the train lines, the irregular operation of the drivers and the poor maintenance, the DF 7G C locomotives frequently fail in individual operations, causing the most losses. The most serious and most influential is the air compressor motor burning. According to statistics, only 27 units were burned in August and October 2008 (some of which were motor self-cooling fan hubs and steel sleeves that could be repaired and the other internal windings were burned out), which caused 5 locomotives to be broken at the same time. The ancient side expressed strong dissatisfaction with this. The ZD316 (A) motor used in the DF7G C-type locomotive is a special DC motor for air compressor designed and manufactured by Zhuzhou Times Group Technology Co., Ltd. The motor is a 4-pole DC motor. The stator part has 4 main poles and 4 additional poles. The self-ventilation is used. The fan is made of cast aluminum wind blade and steel sleeve structure. The blades are radial type, 19 pieces. The main technical parameters are as follows. Burning inside the motor. 2 reasons analysis Due to the serious air leakage in the ancient train line, the air compressor motor of the intermittent working system is in a state of long-term operation, causing the motor temperature rise to exceed the standard and causing burnout. The installation of the Cuban locomotive on-board recorder provides scientific and effective data support for our analysis of faults. The reasons for the failure of the wind pump motor are now briefly analyzed as follows. 2. 1 fatigue work The Cuban trailer air duct system is outdated and the air leakage is serious. The recorder records a large number of 41 fault codes (train tube pressure < 100 kPa). In actual use, the wind pump is also fast and the air is leaking quickly, causing the motor to start frequently. The ZD316(A) type air pump motor is a 40% intermittent cycle working system, but according to the state of the air compressor motor switch recorded by the recorder, after a plurality of multi-time statistical averages, the actual working time ratio of the motor is 50%. Left and right, part of the time period even reached more than 60%, there was a phenomenon of work and rest. 2. 2 heat is difficult to disperse The body of the air compressor motor is located below the cooling chamber, and the ambient temperature is extremely high. This is the root cause from the damage of the burned motor. Allowable temperature rise of the main components of the ZD316(A) type air pump motor. The on-site follow-up measurement results show that the temperature rise of each main component has exceeded the standard. Since we have done some work on the heat dissipation, the dust filter of the auxiliary room has been removed, the hole of the motor has been punched, and it is recommended that some of the locomotives will open the side door of the auxiliary room during operation, especially in November. Since the decline, the air compressor motor has not experienced any burnout failure. 2. 3 poor periphery The first is that the double tower dryer is not working properly, such as not working, the two towers are not converted, etc. Secondly, the dryer should discharge 15% of the air volume of the air pump into the atmosphere for the regeneration of the desiccant, which is intensified in the invisible. The working load of the air compressor motor (in the early stage, the dryer was closed, but due to the humidity of the air line, the electric air contactor air valve was blocked by iron filings, impurities, etc., and it was necessary to check the dredging regularly, adding a lot of work. The amount has changed and the situation has been improved after replacing the dryer control box. In addition, the automatic exhaust valve 12F often works abnormally, so that the air compressor motor is often loaded and started. 2. 4 insurance issues Among the 27 faults in the statistics, all of them were burned by the motor and the fuses were intact, and the insurance was not insured. Considering the failure of the main generator excitation current overcurrent in the past, the two models 52527 and 52530 are used for simple modification test, that is, a shunt is added to connect the air compressor motor current to the microcomputer to control the excitation. The current channel, so that the display can be used to observe the working current of the air compressor motor and record the real-time data. According to the on-site measurement and recorder recording, the normal working current of the air compressor motor is 230 A, which satisfies the rated current of 220 250 A. The starting current is 550 A and the duration is 12 2 s, which is far lower than the maximum starting current of the motor 875 A. Parameter index. In addition, the 95-side wiring of the main circuit of the air compressor motor of the burned motor locomotive is intact, and the long-term flow of large current in the loop can be eliminated. The current air compressor fuse type is RT16 2am type, and the current is changed from 400 A to 355 A. 3 improvement suggestions 3. 1 enhance the heat dissipation of the auxiliary room From the burning condition of the motor shown, the excessive temperature rise of the motor due to the accumulation of heat is the direct cause of the burnout failure, and the heat dissipation of the auxiliary chamber should be increased. Ventilation holes can be added to the side wall of the auxiliary room and the dust filter can be reduced from 4 layers to 12 layers; or the air compressor motor is installed on the floor, which can strengthen the air circulation with the vehicle bottom and heat the accumulated heat. Blowing to the outside through a cooling fan. 3. 2 reduce the rated current of the fuse The second characteristic of the fuse has an inverse time characteristic, that is, when the current is large, the time required for the melt to be blown is short; and when the current is small, the time required for the melt to be blown is longer, or even not blown. . See the current time comparison of common fuses. The RT16 2am ( 355 A ) type fuse used in the Cuban air pump motor is a sealed closed tube fuse with quartz sand as the filler and silver plated grid copper as the melt material. It can be seen that the overload protection function of the fuse is not ideal. Unless the fuse with low rated current can be selected, the rated current can be designed to be lower by the test without the start time of 12 s, such as 250 A. . 3. 3 air compressor motor modification (1) Mechanical performance of the motor itself: 12 of the 27 faults are caused by the looseness of the fan and the steel sleeve of the self-cooling fan, causing the fan to be lost or even stopped. This is a mechanical failure of the motor itself, and the quality should be selected. Good product. (2) Motor power: Select a motor with a higher power (> 22 kW) to give it a greater safety margin. (3) The working system of the motor: use the motor with intermittent working cycle of about 60% or continuous working system. (4) Insulation grade of the motor: The current ZD316(A) type air pump motor has an insulation grade of F grade, and it is recommended to change it to a H-class motor, so that the highest temperature rise can be increased by 25%. 3. 4 switch to single screw air pump If you switch to a high-power or high-insulation wind pump motor, it will inevitably lead to an increase in the volume of the motor. It is necessary to modify the air compressor unit in the existing installation space. It is recommended to use a small-sized single-screw pump instead. In addition to the advantages of small volume, high reliability and good dynamic balance, the screw pump also has the characteristics of forced air transmission, that is, the displacement is almost independent of the exhaust pressure, and the operation is stable and the vibration is small, so that the current use can be avoided. The load becomes heavier due to the increase of the air cylinder pressure in the late stage of the centrifugal pump. 4 Conclusion The method of enhancing the heat dissipation of the auxiliary room and reducing the rated current of the air compressor motor fuses has been tried with different measures in the practice of the Cuban car, and it has also achieved gratifying effects, but this is only a small detail in the existing air system. The repair, if you want to solve the problem of air compressor motor once and for all, it is necessary to retrofit the air compressor unit. Vibratory Screen,Vibrating Screen,Vibratory Screener Blender&Mixing Machine Mixing Machine Co., Ltd. , http://www.nsdryingmachine.com