Daily maintenance and overhaul of INVT's inverters

Maintenance and overhaul of INVT's inverter

    Dust removal, the focus is on the rectifier cabinet The inverter control cabinets and cabinets, rectifier, inverter module and control board cabinet can be removed after the dust removal, if necessary. Whether the air inlet and upper air outlet of the inverter are dusty or blocked due to excessive dust. The frequency converter has a large amount of ventilation due to its own heat dissipation. Therefore, in the future, the surface area dust is very serious, and it is necessary to clean the dust regularly.

2. Open the front door of the inverter and disassemble the rear door. Check the AC and DC busbars for deformation, corrosion, oxidation, and whether the screws at the busbar joints are loose or not. Whether the sturdy screw is loose or not, whether the insulating sheet or the insulating column is fixed for aging cracking or deformation, if it should be replaced in time, re-tighten, and the busbar that has been deformed must be corrected and re-installed.

3, after the dust removal of the circuit board, busbar, etc., carry out the necessary anti-corrosion treatment, apply the insulating varnish, and remove the burr after the busbar that has partially discharged and arced, and then process it. . For the insulation board that has been insulated and broken, the damaged part shall be removed, and the insulation board of the corresponding insulation grade shall be blocked in the vicinity of the damage, and the insulation shall be tightened and tested and deemed to be qualified before being put into use.

4. Whether the fan running and rolling in the rectifier cabinet and the inverter cabinet are normal. When the machine is stopped, roll it by hand to investigate whether the bearing has stuck or noise, and replace the bearing or repair if necessary.

5. Comprehensive inspection of input, rectification and inverter, DC input fast-melting, and found that incineration is replaced in time.

6. Whether the capacitor in the intermediate DC circuit has leakage, whether the casing is expanded, bubbling or deformed, whether the safety valve is broken, and the condition can be used for capacitance capacity, leakage current, and withstand voltage. Test, replace the capacitor that does not meet the requirements, for the new capacitor or long-term use of the unused capacitor, it must be passivated before replacement. The use period of the filter capacitor is generally 5 years. If the use time is more than 5 years, the capacitance capacity, leakage current, and withstand voltage are obviously deviated from the test specifications, and should be replaced partially or completely as appropriate.

7. Conduct electrical inspection on the rectifier, inverter diode and GTO with a multimeter, measure the forward and reverse resistance values, and carefully record in the prepared form beforehand. Whether the resistance between the poles is normal, whether the consistency of the same type of equipment is outstanding, and if necessary, replace it.

8. Check the main touch sensor and other auxiliary touch devices in the A1 and A2 incoming cabinets, and carefully investigate whether the dynamic contacts of each touch sensor have arcing, burrs or surface oxidation, and unevenness. It has been found that such problems should be replaced by their corresponding dynamic contacts to ensure that their touch is secure.

9. Carefully check whether the terminal block is aging or loose, whether there is a hidden fault in the short circuit, whether the connection of the connection wires is firm, whether the wire is damaged or not, and whether the plugs of the circuit boards are firmly connected. Whether the connection between the main power supply line and the main power supply line is reliable, whether there is heat generation and oxidation at the joint, and whether the grounding is outstanding.

10. Whether the reactor has abnormal noise, oscillation or odor.

In addition, conditions can be used to measure the filtered DC waveform, the inverter output waveform, and the input power harmonic components.