Operation With Residual Current Protective Device (Rcd) - Siemens SINAMICS G120C Operating Instructions Manual

Installing
4.9 Connect the line supply, motor and braking resistor
Frame sizes FSD ... FSF
• Operate the converter under the following ambient conditions:
– Pollution degree 2
– Overvoltages category III
4.9.6

Operation with residual current protective device (RCD)

Fire or electric shock due to unsuitable residual-current protective devices
The converter may create a current through the protective conductor. The current through the
protective conductor can cause the residual current device (RCD) or residual current monitor
(RCM) to incorrectly trip (nuisance trip). In the case of a ground fault, the fault current can
contain a DC component, which prevents the RCD or RCM from tripping, with the risk of
subsequent fire or electric shock.
• Use the protection and monitoring devices recommended in the documentation.
Protection and monitoring equipment
To provide protection against short-circuit, use the overcurrent devices listed in Technical data
(fuses, circuit breakers etc.).
If the earth fault loop impedance of the line supply at the infeed point is too high to ensure
that the overcurrent protective device disconnects within the stipulated time in the case of
insulation failure (ground fault, fault to frame), then you must use additional residual current
protective devices RCD, type B.
In order that an RCD does not unnecessarily trip as a result of operational leakage currents,
the following preconditions must be fulfilled:
• The neutral point of the line supply is grounded.
• For converters with rated input currents ≤ 80 A referred to LO, use a Siemens SIQUENCE RCCB
(series 5SV364.-4), type B, short-time delayed [K] with a rated residual current of 300 mA.
Connect the RCCB in series with the overcurrent protective devices.
• For converters with rated input currents ≤ 160 A referred to LO, use a Siemens residual
current device RCD520B (3VA9113-0RL21) mounted onto a Siemens molded case circuit
breaker (series 3VA1).
Recommended settings:
– Response characteristic B
– Residual current trip level 300 mA
– Response delay ≥ 0.06 s
78
WARNING
Operating Instructions, 02/2023, FW V4.7 SP14, A5E34263257B AK
SINAMICS G120C Converters