Siemens SINAMICS S120 Combi Manual page 314

Service and maintenance
13.4 Forming the DC link capacitors
Forming circuit
The S120 Combi Power Module has internal PTC resistors to pre-charge the DC-link
capacitors. The resistors can be used to form the DC-link capacitors of the S120 Combi
Module as well as the expansion axes (Motors Modules Booksize Compact).
During the forming process, it is not permissible for the S120 Combi Power Module to
receive a switch-on command. Therefore, disconnect the 24 V power supply to the S120
Combi Power Module.
Procedure
S120 Combi Power Module
1. Connect the S120 Combi Power Module with a line reactor to the line supply (see the
connection example in Section Interface description (Page 68)).
2. Keep the module connected to the line supply for approx. 1 hour without issuing a switch-
on command.
Expansion axis (Motor Module Booksize Compact)
1. Connect the expansion axis to be formed to the DC link of the S120 Combi Power
Module.
2. Connect the S120 Combi Power Module with a line reactor to the line supply (see Section
Connection examples (Page 83)).
3. Keep the S120 Combi Power Module and the expansion axis connected to the line supply
for approx. 1 hour without issuing a switch-on command.
Electric shock due to the residual charge of the DC-link capacitors
Due to the DC-link capacitors, a hazardous voltage is present in the DC link for up to
five minutes after the power supply has been switched off.
Contact with live parts can result in death or serious injury.
• Do not open the protective cover of the DC link until five minutes have elapsed.
• Only operate the S120 Combi with the DC-link protective cover closed.
• Do not continue to operate damaged components.
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WARNING
Ensure that you press the release catch when opening the protective cover for the DC
link. A suitable tool (e.g. screwdriver or supplied release tool) must be used for this
purpose.
SINAMICS S120 Combi
Manual, 11/2017, 6SL3097-4AV00-0BP7