Line Supply Connection Via Residual-Current Devices; Residual-Current Operated Circuit Breakers (Rcd) - Siemens Sinamics S120 Manual

3.4

Line supply connection via residual-current devices

Selectively tripping, AC/DC-sensitive residual-current devices (type B) can be used in
addition to the overcurrent protection devices.
Residual-current devices have to be installed if the power supply conditions in terms of short-
circuit power and loop impedance at the infeed point are not such that the installed
overcurrent protection devices will trip within the prescribed period if a fault occurs.
3.4.1

Residual-current operated circuit breakers (RCD)

Residual-current operated circuit breakers (RCD) can be used in addition to the overcurrent
protection devices provided. They are the preferred solution for operation on TT systems.
Note
Operation on residual-current operated circuit breakers is currently only possible with Line
Modules up to and including 36 kW.
Observe the following conditions when using residual-current operated circuit breakers:
● Only use a delayed tripping, selective AC/DC-sensitive residual-current operated circuit
● Ensure that the loop impedance is maintained corresponding to local installation
● Check the total length of the shielded power cables (motor cables incl. line supply
● Only operate the system with the recommended line filters.
● If you connect residual-current devices in series, then they must all have the same
● Ensure that the switching elements (disconnector unit, contactors) for connecting and
Booksize Power Units
Manual, (GH2), 04/2014, 6SL3097-4AC00-0BP6
breaker, type B.
regulations.
conductors from line filters to the connecting terminals of the Line Module) in the drive
line-up. The total length must be less than 350 m.
characteristics.
disconnecting the drive system have max. 35 ms delay time between the closing/opening
of the individual main contacts.
Line connection and line-side power components
3.4 Line supply connection via residual-current devices
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