Key Points for Operation and Maintenance of VFD in Summer

Summer is the frequent season of frequency converter failures. To ensure long-term stable and reliable operation of the frequency converter, the key lies in daily maintenance. Unnecessary accidental downtime is caused. During the maintenance of the inverter in summer, the user must pay attention to the temperature of the installation environment of the inverter, and regularly clean the dust inside the inverter to ensure the smoothness of the cooling air path. Strengthen inspections and improve the surrounding environment of inverters, motors and lines. Check whether the wiring terminals are tight, ensure the correct and reliable connection of each electrical return, and prevent unnecessary downtime accidents.

1. Confirmation of the installation environment of the VFD

1. Ambient temperature: The inverter generally requires a low ambient temperature of -5°C and a high ambient temperature of 40°C. A large number of studies have shown that the failure rate of the inverter increases exponentially with the increase of temperature, and the service life decreases exponentially with the increase of temperature. If the ambient temperature rises by 10 degrees, the service life of the inverter will be halved. In summer, when the temperature is high, condensation is prone to occur inside the frequency converter, and its insulation performance will be greatly reduced, which may even cause a short circuit accident. The ventilation and heat dissipation of the inverter installation site should be strengthened.
2. Summer is a rainy season, and rainwater should be prevented from entering the inverter (for example, rainwater enters along the air outlet of the wind tunnel)
3. Corrosive gas: If there is corrosive gas in the use environment, it will not only corrode the leads of components, printed circuit boards, etc., but also accelerate the aging of plastic devices and reduce the insulation performance; if there is acid or alkaline corrosion around the inverter Inert gas, please provide targeted solutions according to the actual situation on site.
4. Vibration and shock: When the inverter cabinet is subject to mechanical vibration and shock, it will cause poor electrical contact. Therefore, after the equipment has been in operation for a period of time, its wiring should be checked and maintained.

2. Matters needing attention in daily inspection

1. Strengthen the inspection and arrange special personnel to be responsible for the daily maintenance of the inverter;
2. Operation data record: Write the operation record table of the inverter, regularly record the operation data of the inverter and the motor, including the output frequency, output current, output voltage and other parameters of the inverter, and compare them with reasonable data to facilitate the early detection of potential failures.
3. Ensure that the ambient temperature of the inverter room is between -5 and 35°C. Set up special personnel to check whether the cooling fan on the top of the inverter cabinet is normal and whether the filter screen on the cabinet door is blocked. Make sure that the cooling air duct is unobstructed. The specific method is: put a piece of A4 printing paper of standard thickness on the filter screen of the cabinet door, and the paper should be adsorbed on the air inlet window. In order to ensure the smoothness of the cooling air passage, the filter screen should be cleaned once a week. If the site environment is dusty, the cleaning interval should be shortened.
4. Environmental monitoring: When the temperature is high in summer, the ventilation of the frequency conversion installation site should be strengthened. Make sure that there is no excessive dust, acid, salt, corrosive and explosive gas in the surrounding air, and prevent the inverter from being exposed to direct sunlight or placing it close to heat sources; summer is a rainy season, and rainwater should be prevented from entering the inverter (for example, rainwater along the wind into the air outlet).
5. Check the tightness of all electrical connections, check that there are no abnormal discharge traces in each circuit, no strange smell, discoloration, cracks, damage, etc.
6. The frequency conversion room must be kept clean and tidy, and should be cleaned at any time according to the actual situation on site.
7. The ventilation and lighting of the frequency conversion room must be good, and the ventilation and heat dissipation equipment (air conditioner, ventilation fan, etc.) can operate normally.

3. Items to be maintained after the inverter stops

1. Use a vacuum cleaner with a plastic nozzle to clean the inside and outside of the inverter cabinet to ensure that there is no excessive dust around the equipment.
2. Check the ventilation and lighting of the frequency conversion room, and the ventilation equipment can operate normally.
3. Check that the connection between the cables inside the inverter is correct and reliable.
4. Check that all grounding in the inverter cabinet should be reliable, and the grounding points should not be rusted.
5. Every six months, the nuts connecting the cables inside the inverter should be tightened again.
6. Check the tightness of all electrical connections, check that there are no abnormal discharge traces in each circuit, no strange smell, discoloration, cracks, damage, etc.
7. After each maintenance of the inverter, carefully check whether there are any missing screws and wires, etc., to prevent short-circuit accidents caused by small metal objects. Especially after making major changes to the electrical circuit, ensure that the connection of the electrical connection line is correct and reliable to prevent the occurrence of “reverse power transmission” accidents.