Siemens SINAMICS S120 Manual page 488

DC link components
8.2 Braking Module Booksize
Rapid discharge
Furthermore, the Braking Module Booksize can used with a braking resistor to quickly
discharge the DC link capacitors The DC link is discharged in a controlled manner via the
braking resistor once the infeed unit has been switched off and the line-up has been
disconnected from the line supply (e.g. via the main switch or line contactor). The function
can be activated via a digital input on the Braking Module. A quick discharge makes sense,
for example, when maintenance tasks are to be performed at the Motor Module and/or motor
installation (reduction of the discharge time).
Danger to life when live parts are touched after rapid discharge
On completion of quick discharge, a voltage of 30 V is still present at the DC link. If the fast
discharge is interrupted before it has been completed, then this voltage can be more than
60 V. Touching live components can result in death or severe injury.
• Check the DC link to ensure that it is in a no voltage state before starting any work.
NOTICE
Damage to the Motor Module or connected motors for a fast discharge
For a fast discharge, the Motor Module or the connected motors can be damaged.
• For a rapid discharge, fully disconnect the drive system from the line supply.
• The motors must be at a standstill.
Monitoring functions
● Automatic detection of braking resistors and braking power monitoring
● I
● Temperature monitoring of the Braking Module
● Short circuit and overload detection
● Ground fault detection
488
WARNING
t monitoring of the braking resistors.
2
Booksize Power Units
Manual, (GH2), 07/2016, 6SL3097-4AC00-0BP8