Storage; Maintenance - KEB COMBIVERT P6 Instruction Manual

Annex A
5.3

Storage

The DC link of the KEB COMBIVERT is equipped with electrolytic capacitors. If electrolytic
capacitors are stored de-energized, the oxide film acting as dielectric medium reacts with
the acidic electrolyte and degrades itself slowly. This affects the dielectric strength and the
capacity.
If the capacitor starts running with rated voltage, it is tried to build the oxide film abrupt again.
This generates heat and gas and destroys the capacitor.
In order to avoid defectives, the KEB COMBIVERT must be commissioned depending on the
storage period according to the following table:
Storage period < 1 year
• Start-up without special measures
Storage period 1...2 years
• Operate inverter one hour without modulation
Storage period 2...3 years
• Remove all cables from the power circuit; Remove X2A and X2B.
• Connect variable transformer to inverter input
• Increase variable transformer slowly (>1 min) to indicated input voltage and remain at
least for the specified time.
Storage period > 3 years
• Input voltages as before, however double the times per year. Eventually change capaci-
tors.
Table 5:
After performing this re-commissioning, the KEB COMBIVERT can be operated at rated con-
ditions, or it can be put back to another storage.
5.4

Maintenance

All work may be performed by qualified personnel only. Please observe the follwing safety
rules:
• Disconnect mains power supply and energy storage
• Prevent unintentional restart
• Await discharge time of the capacitors (5 minutes)
• Verify by measurement that the unit is free of voltage
In order to avoid premature ageing and avoidable malfunctions, the measures mentioned
below must be carried out in the appropriate cycle.
44
Input voltage
0...280 V
280...400 V
400...500 V
Measures after long storage time
Duration
15 min
15 min
1 h