Maintenance and Fault Diagnosis of Low Voltage Inverter

1. Necessity of maintenance and fault diagnosis of 6SE70 low voltage inverter

In order to ensure the stability, safety, rationality and efficiency of electrical equipment, reduce the impact of failures on production, and eliminate the weak links of production failures, maintenance and maintenance services for electrical equipment are required.

1) The lifespan of electrical components is different. Replacing the components (fans, capacitors, cables) at the end of their lifespan in time can extend the service life of the entire machine.

2) Timely identify components with quality risks and eliminate potential faults.

3) Remove dirt and dust promptly and professionally to avoid accelerated aging and short circuit failure caused by high temperature operation of the equipment.

4) Discover and adjust optimal operating parameters in a timely manner.

5) Promptly check for looseness and local corrosion of some connectors.

6) Each device is inspected quarterly and an equipment operation report is issued to enable managers to intuitively understand the usage of each device.

The figure shows the bathtub curve of the inverter's service life. In the figure, stage A is the new product running-in period, stage B is the efficient and stable life period, and stage C is the performance decline failure period. In stage A, the equipment is still in the running-in period, and some problems will occur, but the duration is short; stage B is the inverter's stabilization period, during which the inverter has reliable performance and stable operation; in stage C, the inverter has been used for a period of time, and a lot of oil, conductive dust, etc. will accumulate inside the inverter, and the components will also begin to age, with a much higher failure rate than stage B. The purpose of the inverter general contracting service is to extend the inverter's stage B time and ensure that problems in stage C are solved in a timely manner, so as to ensure the planning and safety of production and reduce the total cost of equipment use.

2. 6SE70 low voltage inverter maintenance and fault diagnosis content

Conduct in-depth maintenance and inspection on the frequency conversion system to eliminate existing or potential hidden dangers. At the same time, use professional testing tools to conduct in-depth cleaning and performance testing on the components inside the frequency converter, IGBT, rectifier bridge, capacitor, power system, bus cable, etc.

1. Transmission equipment file creation

A. We conduct routine filing based on the company's existing online transmission equipment and spare parts.

B. Back up related software to restore faulty equipment in a timely manner.

C. Establish equipment maintenance and repair record files and status assessment files.

2. Preventive professional maintenance and repair content

A. Parameter Check

A.1 Parameter backup

A.2 Fault record check

B Parts Maintenance

B.1 Check the overall status of the frequency converter

B.2 Heat dissipation channel inspection and cleaning

B.3 Fan operation inspection

B.4 Check the thermal grease of power module and the fastening of power module (whether to use depends on the years of equipment investment)

B.5 Circuit board corrosion and aging device inspection

B.6 Internal wiring inspection

C Static calibration

C.1 Static measurement of rectifier bridge (upper half bridge, lower half bridge)

C.2 IGBT static measurement (upper half bridge, lower half bridge)

D Functional testing

D.1 Check the charging circuit, charging resistor and diode

D.2 DC capacitor and DC bus charge and discharge inspection

D.3 Check the fan starting capacitor capacity

D.4 Rectifier module firing angle resistance measurement

D.5 IGBT trigger conduction measurement

E Insulation test

E.1 Motor insulation test

E.2 Cable insulation testing

F Control panel detection

F.1 Control panel display test

F.2 Control panel button detection

G Run Test

G.1 All cables are properly connected;

G.2 There is no foreign matter in the inverter;

G.3 All equipment covers have been closed;

G.4 The equipment grounding device has been removed;

G.5 The motor and process startup procedures are normal;

G.6 Power-on no-load test;

G.7 Power-on load test;

G.8 Monitor and record the equipment output status, and include the final results in the maintenance report.

Through the above maintenance and measurement, potential faults of the inverter can be checked, existing faults can be solved, and faulty components can be replaced to ensure the normal operation of the inverter!