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Entry type: FAQ Entry ID: 1960441, Entry date: 08/12/2014
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MICROMASTER, SINAMICS V20/G110/G120/G120C/G120P: Forming the DC link capacitors.

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If frequency inverters (MICROMASTER, SINAMICS V20/G110/G120C/G120 with PM240) are not operational for a longer period of time, then the DC link capacitors must be formed corresponding to the data in the individual Operating Instructions.

After what time period do the DC link capacitors have to be re-formed?
What is the procedure when forming DC link capacitors?


It is important that the storage time is calculated from the date of manufacture and not when the drive unit is actually supplied. The date of manufacture is coded in the serial number.
Please refer to the following document for information on the serial number MICROMASTER 4 (MM4), SINAMICS G120x/G110x: 7016746

Please refer to the Operating Instructions for information on the serial number SINAMICS V20: Inverter rating plate 


In principle this is valid for the following:
Storage period of up to 1 year:
No additional measures are required.

Storage period from 1 - 2 years:
Connect the frequency inverter to the power supply 1 hour BEFORE the first ON command.

Storage periods from 2 - 3 years:
Using a regulated power supply - supply the frequency inverter for:

  • 30 minutes with 25% of the rated voltage, then
  • 30 minutes with 50% of the rated voltage, then
  • 30 minutes with 75% of the rated voltage, then
  • 30 minutes with 100% of the rated voltage

Storage period for 3 and more years:
Using a regulated power supply - supply the frequency inverter for:

  • 2 hours with 25% of the rated voltage, then
  • 2 hours with 50% of the rated voltage, then
  • 2 hours with 75% of the rated voltage, then
  • 2 hours with 100% of the rated voltage.

Procedure with regulated power supply:
The regulated power supply is selected depending on the required line supply voltage of the frequency inverter. For a frequency inverter with a line supply voltage of 1-ph. / 3-ph. 230V AC, a single-phase adjustable transformer with e.g. 1-ph. 230V AC / 2A can be connected at the input of the frequency inverter. The frequency inverter is connected to the power supply through its input terminals, whereby both 1-ph. as well as also 3-ph. frequency inverters can be fed with single-phase (L+ at L1 and N at L2 or L3 terminals). All of the DC link capacitors are uniformly charged due to the fact that a rectifier is being used.

For frequency inverters that require higher voltages, it only has to be ensured that the required voltage (e.g. 400V) is available. A power supply with a low rating can be selected as almost no current is drawn when forming the capacitors (2A should be enough).

Note


Please refer to MICROMASTER Operating Instruction. Chapter Installation after a Period of Storage


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