The daily maintenance and maintenance of frequency converter is the guarantee of safe work of frequency converter. If the daily maintenance and maintenance work is done well, the problems can be found and handled in time, which can make the inverter work in the best state for a long time, reduce the occurrence of shutdown faults and improve the efficiency of frequency converter.

In the daily operation of the frequency converter, the operation state of the frequency converter can be judged by hearing, visual inspection, touch and smell. The general inspection contents include:

1) Whether the surrounding environment, temperature and humidity meet the requirements.

2) Whether there is dust on the air inlet and outlet of frequency converter and whether it is blocked by dust.

3) Whether the noise, vibration and smell of frequency converter are within normal range.

4) Whether the operation parameters and panel display of frequency converter are normal.

Low voltage small frequency converter refers to the low-power inverter working on the low-voltage power grid 380V (220V). This kind of frequency converter is mostly installed in the control cabinet in the form of vertical wall hanging, and its regular maintenance mainly includes:

(1) Regular inspection of dust removal

When the frequency converter is working, due to the fan blowing and heat dissipation and the electrostatic adsorption of components, it is easy to accumulate dust in the inverter interior and vent, especially when there are many dust and flocs on the working site, the dust accumulation will be more serious. Dust accumulation can cause poor heat dissipation of frequency converter, increase internal temperature, reduce the service life of frequency converter or cause overheating trip. Depending on the dust accumulation, dust removal can be carried out regularly. When dedusting, the power supply should be cut off first. After the energy storage capacitor of frequency converter is fully discharged (5 ~ 10min), open the machine cover. Do not rush to remove dust after opening the machine cover. Carefully observe the internal structure. If necessary, draw a sketch and make a written record, so as to avoid the influence of micro switch displacement and loose plug on the normal operation of frequency converter after dust removal. When dedusting, clean the accumulated dust with brush or compressed air. Operation should be very careful, do not touch the components and micro switches, connector terminals, etc., in order to avoid the inverter can not work normally after dust removal.

(2) Regularly check the main parameters of the circuit

Whether some main parameters of frequency converter are within the specified range is the sign of safe operation of frequency converter. Such as the main circuit and control circuit voltage is normal; filter capacitor leakage and capacity is reduced. In addition, most of the main parameters of the frequency converter are displayed on the panel, so whether the panel display is clear or not and whether there are missing characters should also be the contents of the inspection.

(3) Check the peripheral circuit and facilities of frequency converter regularly

Mainly check whether the braking resistance, reactor, relay and contactor are normal; whether the connecting wire is loose; whether the fan in the cabinet works normally; whether the air duct is unblocked; whether the leads are damaged or loose.

(4) Judge the service life of components according to maintenance information

The filter capacitance of the main circuit of the inverter decreases with the increase of the service time. When it drops to 85% of the initial capacity, it needs to be replaced. The ventilation fan also has a service life. When the service time exceeds (3 ~ 4) × 104H, it also needs to be replaced. In the high-grade inverter, the panel display can display the capacity of the main circuit capacitor and the life of the fan to prompt timely replacement. The electrolytic capacitor of the control circuit can not be measured and displayed. Its life should be inferred by multiplying the accumulated working time by the life factor determined by the internal temperature rise of the frequency converter. The cumulative operation time is in H, and the minimum is 6 × 104H.