Analysis and Improvement of Burning Causes of HX_D3 Locomotive Air Compressor

Analysis and Improvement of Burning Causes of HX_D3 Locomotive Air Compressor

On March 20, 2009, electric locomotives and urban rail vehicles were used to analyze the causes of burning of HXD3 locomotive air compressors and improve the technical department of Nanjing East Locomotive Depot of Jiangsu Jianfeng, Nanjing 210046, Jiangsu Province, taking effective measures and achieving good results. .

1Overview The Type 3 locomotive is a high-power AC drive electric locomotive developed by Dalian Locomotive & Rolling Stock Co., Ltd. and Toshiba Corporation of Japan. It is a technology introduction project of the Ministry of Railways. The locomotive air supply equipment uses a technologically advanced screw air compressor unit. The compressor unit adopts cast aluminum oil and gas cylinder, built-in oil separator, air outlet under the cooler, temperature-controlled Oil Filter structure, self-contained temperature protection and pressure protection.

Since the official launch of the Type 3 locomotive in January 2007, the compressor unit has been stable and provides a good source of wind for the locomotive. However, on February 16, 2008, when the 30024 locomotive was inspected, it was found that the external paint of the air compressor of the air compressor fell off, the lubricating oil pipeline and the oil filter turned black, the heat dissipation ribs were partially black, and the unit could not start normally when the pump wind was tested. The locomotive control protection switch is not disconnected, and the control system has no faults. The car was inspected and found that the air compressor was stuck.

2 Failure phenomenon Through the above phenomenon, it is preliminarily judged that the air compressor has been burnt, so the air compressor is decomposed and inspected, and it is found that the air Filter Element and the safety filter are partially black, and the rest are in primary colors; the motor is normally checked and the unit is inspected. After disintegration, the motor rotates flexibly, the insulation detection is normal; the appearance inspection cooling impeller is normal, no deformation and crack, the coupling bolts are not loose, the elastomer is normal, not broken; the oil filter is dry, there is black coke, there is The burnt smell and the apron burned out; the temperature of the spring gland on the temperature controller is brown, the rubber ring loses its elasticity, the collar is not abnormal, and there is a dark brown coke in the valve body; the fine oil separator decomposes in the oil and gas cylinder In 3 stages, the sheath was burned and only the residue was observed. There is rust on the fine oil separator, and the filter material is black-focused.

The pressure maintaining valve valve plate is black, the spring rubber ring is complete, the lower part of the piston is black, the piston apron is complete; the inlet valve check valve face is black, the action is flexible, the rubber ring is lost, the backstop function is lost, and the intake end has Black coke condensate; the spring seat of the unloading valve is complete, the action is normal, the piston is discolored, the apron is complete, the unloading nozzle is complete, and the surface is brown; the inner surface of the oil and gas cylinder has a layer of brown coke, no lubricating oil; The screw head is disassembled, the end face of the rotor is worn, the profile is broken, the surface is brown, and there is black carbon deposit in the tail pipe; the oil return pipe check valve is completely blocked, and the valve body has a gathering of coke.

The temperature switch and pressure switch are detected to operate normally. The cooler surface is normal, the fins are not damaged, and the water pressure test has no leakage.

3 Analysis of the cause of the failure The comprehensive failure phenomenon, we believe that the air compressor is caused by the lack of lubricating oil cooling of the screw pair, the unit discharge temperature is too high, resulting in burning failure. The high temperature failure caused by the lack of oil in the screw air compressor mainly has the following development stages. When the oil shortage of the unit is lower than 2.6, the operation of the unit will cause the oil level in the oil cylinder to be lower than the oil outlet, resulting in the lubricating oil pipeline. The amount of lubricating oil is insufficient. When the temperature is higher than the standard working condition, the separation effect of the fine oil separator is deteriorated, the oil content of the exhaust gas is increased, and the lubricating oil is accelerated to be lost. This phase belongs to the recoverable phase. As long as the replenishing lubricant is inspected in time, the air compressor can be fully restored to normal working condition.

In the first stage, the compressor unit loses its cooling function due to the sharp decrease in the amount of lubricating oil, and the exhaust gas temperature rises sharply. A small amount of lubricating oil mixed in the exhaust gas is carbonized due to high temperature, and carbonized particles accumulate on the oil filter surface and the oil separator surface. Resistance increases. The process will gradually accumulate in multiple operations. After the temperature of the unit rises, the temperature switch of the air compressor will operate, and the unit will be suspended. After a period of time, the temperature will gradually drop and the temperature switch will return to normal. The unit will re-enter under the command of the locomotive. jobs. As a result of this cycle, carbonization in the body is accumulated. This stage is an unrecoverable stage, but as long as it is discovered in time and the oil filter fine separator and lubricating oil are replaced, the unit can be returned to normal operation.

In the first stage, when too much carbon is accumulated in the lubricating oil, the oil filter is finally blocked, and the lubricating oil injected into the head is lower than the safe value; the temperature of the head climbing is too high, and a large amount of carbon deposits on the surface of the fine separator. The carbonization gap of the oil filter material is blocked, the function is lost, and the lubricating oil is completely lost in an instant; on the other hand, the carbon deposit gathers in the pipeline, thereby invalidating the discharge and return pipeline. This stage is already in an uncontrollable stage, and the air compressor cannot be returned to normal operation by ordinary maintenance means.

In the first stage, the screw pair was stuck due to the screw dry friction, and the unit could not continue to operate, causing the working current of the drive motor to be too large and burned.

Through the analysis of the inspection results, the air compressor failure has been developed to the first stage causing the screw pair to stick, but the motor has not been burned.

The lack of oil in the air compressor is mainly due to the special installation design of the air compressor of the Type 3 locomotive. Its cooler is installed downwards, and the cooling air is discharged from the lower part of the locomotive through the air duct. The cooler of the air compressor is located in the unit. At the bottom, the air compressor under the wind faces the thermometer effect and the jelly effect of the lubricating oil in winter. The thermometer effect refers to the phenomenon that the temperature lowers the surface of the lubricating oil, especially in the lower fan group. The unit cooler is located at the bottom, and a large amount of lubricating oil is stored in the area. When the temperature is lowered, the volume shrinkage of the lubricating oil will inevitably cause the oil level of the upper oil and gas cylinder to decrease. In combination with other unfavorable factors, the lubricating oil surface is likely to be lower than the lubricating oil outlet. When it is lower than the oil outlet, the oil supply pipeline will enter the air, which will inevitably cause the engine to be insufficiently supplied and burned. The jelly effect means that the lubricating oil exists in the form of a gel in the pipeline at a low temperature, and the air compressor may be burned when the air compressor is started at a low temperature.

February 2008 was the climatic condition of the snowstorm. The locomotive was running between Jinan and Xuzhou on the Beijing-Shanghai line. The nighttime temperature was lower than 10, which was very different from the normal working temperature of the air compressor, resulting in a strong thermometer effect. In addition, the unit was directly operated between Jinan and Xuzhou before the failure of the unit, and the oil level check oil filling work was not in place, thus causing the failure.

4 Improvement measures and recommendations After the cause of air compressor burnout is ascertained, the measures are quickly formulated on the section, and the routine maintenance requirements of the screw compressor unit, the operation of lubricating oil level check and oil quantity supplementation, and the organization of force are all On the 3rd type locomotive, the compressor group conducted a general oil survey, and found that 12 units had low oil volume, and immediately organized the unit to supplement the amount of lubricating oil. After this replenishment, there was no similar accident in this type of locomotive compressor unit.

Since the compressor unit uses a down-cooling design, the radiator is at the bottom of the oil circulation system, and when cooled, there is a large amount of lubricating oil in the radiator.

Through many calculations and tests, we can reduce the radiator capacity by 500 without affecting the overall performance of the compressor unit, which improves the oil storage ratio between the radiator and the oil cylinder. The effect of the thermometer effect. In order to prevent the expansion of the fault in the absence of oil, we propose to improve the oil temperature detection and protection system, and increase the compressor failure alarm function on the locomotive control system. When the compressor is running, the compressor control power supply is automatically cut off. The protection compressor is not put back into work under the fault condition, and an alarm signal is sent to the flight attendant, so that the locomotive can be processed in time after returning to the section.

5 Conclusion The screw air compressor unit used in the HXD3 locomotive has been very stable since its application. As the compressor unit is used in large-scale loading on H and 3 locomotives, it is still necessary to improve the daily maintenance of the compressor unit, to provide support for better guarantee of the reliability of the brake system, and to ensure the safe operation of the locomotive.

1 Xing Ziwen. Theoretical design and application of screw compressors Beijing machinery industry, newsletter Guangzhou Metro Line 28 extension line first vehicle in CSR Zhuzhou Electric Locomotive Co., Ltd. on March 19, 2009, Guangzhou Metro Line 28 extension line first line in the vehicle CSR Zhuzhou Electric Locomotive Co., Ltd. dropped the car.

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