The working environment of the crane is abominable, and most of it works in the environment of high temperature, high dust, and even in the environment containing harmful gases. According to the actual working environment, such as the metallurgical crane electric room need to take heat insulation and dust to increase the cooling air cooler and other cooling measures.
Frequency converter general installation environment requirements: minimum ambient temperature -10 C, the highest environmental temperature of 40 degrees. Studies have shown that the failure rate of the transducer increases exponentially with the increase of temperature, and the service life decreases exponentially with the increase of temperature. The life of the converter will be reduced by half if the ambient temperature is increased by 10 degrees. Summer is the frequent season of frequency converter failure, to ensure the long-term stability and reliable operation of the frequency converter, the key is to the daily maintenance.
Precautions for installation the of frequency converter
When installing the frequency converter, please pay attention to the following points:
- The installation space needs to ensure that the frequency converter has sufficient heat dissipation space. When space is reserved, please consider the heat dissipation of other devices in the cabinet.
- Please install the frequency converter vertically to facilitate the upward emission of heat. If there are a number of converters in the cabinet, please install it in parallel. Please install the thermal baffle on the crane when the frequency converter needs to be installed on upside and downside in the crane
- Please make sure that the flame retardant material is used as the mounting bracket for the mounting bracket.
- For the application of metal dust, it is suggested that the installation of a radiator cabinet be adopted. At this time the full – sealed cabinet space should be as large as possible.
- Downtime maintenance of frequency converter
- Monitor and record the display parameters on the touch screen of the inverter, and find that the exception should be reflected immediately.
- Monitoring and recording the ambient temperature of the VVVF room, the ambient temperature should be between -10 and 40.
- The filter net on the converter cabinet usually should be cleaned once a week; if there is more dust in the working environment, the clearance interval should be shortened according to the actual situation.
- In the normal operation of the inverter, a standard thickness of A4 paper should be adsorbed on the door into the air filter net.
- The frequency conversion room must be kept clean and should be cleaned at any time according to the actual situation in the field.
- The ventilation and lighting of the frequency conversion room must be good, and the ventilation equipment can operate normally.
- The temperature of the outlet of the power unit cabinet of the inverter cannot exceed 55 degrees C.
- Precautions for use of inverter when it stops
- Use a vacuum cleaner with a plastic nozzle to thoroughly clean the inside and outside of the inverter cabinet to ensure that there is no excessive dust around the equipment.
- The ventilation and lighting of the frequency conversion room must be good, and the ventilation equipment can operate normally.
- Check the ventilation of the inverter room, lighting, ventilation equipment to normal operation.
- Check all grounding in the inverter cabinet, all of them should be reliable, no rust at the grounding point.
- Check the inverter bypass cabinet high-voltage switch operation whether are normal and can be properly closing and breaking.
- After commissioning of the inverter, please re-check the nuts that fasten the internal cables of the inverter.
- Within six months, fasten the nuts of the internal cable of the inverter once more.
- After six months, fasten the nuts of the inverter’s internal cables once every six months.
- After the inverter resumes operation for a long time, it should measure the insulation of the inverter (including the phase-shifting transformer and the main circuit of bypass cabinet) and should use 1500V megameter. After the test insulation qualified, can start the frequency changer.
Inverter routine maintenance
- Strengthen the inspection, arranging someone responsible for the daily maintenance of the inverter;
- Run the data record.
- Write inverter running record list, regularly record inverter and a motor running data, including inverter output frequency, output current, output voltage, inverter internal DC voltage, radiator temperature and other parameters, and reasonable data comparison to facilitate early Found hidden trouble
- Ensure that the inverter room ambient temperature -10 ~ 40 ℃. Set someone to detect inverter cooling fan roof is normal, the door filter is clogged. Make sure that the cooling air duct is clear. The specific method is: a standard thickness of A4 paper on the filter on the door, the paper should be adsorbed on the inlet window.
- In order to ensure the smoothness of the cooling air duct, the filter should be cleaned once a week. If there is more dust on the site, the cleaning interval should also be shortened.
- At any time record and monitor the inverter operating frequency, current and phase-shifting transformer temperature. Phase-shift transformer temperature cannot exceed 130 ℃.
Environmental monitoring
- When the temperature is higher in summer, the ventilation in the frequency conversion installation site should be strengthened. Make sure there is no excessive dust, acid, salt, corrosive and explosive gas in the surrounding air;
- Summer is a rainy season, to prevent the installation of the inverter environment, no raindrops into the inverter.
- Check the tightness of all electrical connections to see no abnormal discharge traces of each circuit, no strange odor, discoloration, cracks, damage and so on.
- After each maintenance of the inverter, it is necessary to carefully check whether there are missing screws and wires, etc., to prevent small metal objects caused by the short-circuiting inverter. Especially after making major changes to the electric circuit, ensure that the connection of the electric connecting wire is correct and reliable and prevent the occurrence of “back-in” accident.
Conclusion
In short, during summer crane inverter maintenance, pay attention to the temperature of the inverter installation environment, regularly clean the dust inside the inverter to ensure the smoothness of the cooling air duct. Strengthen inspection to improve the frequency converter, motor, and the surrounding environment. Check the terminal is tightened, to ensure that the electrical back to the correct and reliable connection.
Cranes in use, the movement of parts will inevitably wear, loose connectors, oil deterioration, corrosion of metal structures, causing the crane’s technical performance, economic performance and safety performance to varying degrees. Therefore, the crane parts wear has not yet reached the extent of the crane failure, in order to prevent and eliminate hidden dangers, to ensure that the crane is often in good condition, the crane should be maintained and maintained. Through the maintenance of the crane, crane or mechanism to effectively extend the repair interval, including the overhaul cycle, to prevent unnecessary downtime, thereby extending the service life of cranes.