Operating An Active Interface Module Chassis-2 On An Ungrounded Supply System (It System); Pre-Charging Input Circuit For Active Interface Modules Chassis-2 - Siemens SINAMICS S120 Equipment Manual

4.7.7 Operating an Active Interface Module Chassis-2 on an ungrounded supply
system (IT system)
When operating a Active Interface Module Chassis-2 on an ungrounded line supply (IT line
system), an isolating transformer must be connected at terminal strip X609 upstream of the
fan power supply.
NOTICE
Damage to the device if an isolating transformer is not used when connected to an
ungrounded line supply
If, for an ungrounded line supply (IT line system), an isolating transformer is not connected
upstream of the fan power supply, then this can cause significant damage to the device.
• For an ungrounded line supply system (IT system), connect an isolating transformer
4.7.8

Pre-charging input circuit for Active Interface Modules Chassis-2

Description
The pre-charging input circuit ensures there is a current-limited pre-charge of the DC link
capacitors of the Active Line Module Chassis-2 and the connected Motor Modules during the
switch-on procedure.
After pre-charging is complete, the main contactor is closed and the pre-charging input
circuit is bridged, then the Active Interface Module Chassis-2 is connected directly to the
supply system.
The precharging circuit comprises a precharging contactor, precharging resistors and a main
contactor; the circuit must be protected against overcurrent using suitable protection
elements.
The precharging is monitored via feedback from the contactors to the Active Line Module
Chassis-2.
To achieve or to increase the permissible DC link capacitance, the precharging resistors
must or can be connected in parallel in each phase.
The specifications regarding connecting precharging resistors in parallel and the DC link
capacitance are included in the technical data of the Active Line Module Chassis-2.
NOTICE
Damage to the units if the pre-charging input circuit is faulty
If the pre-charging input circuit is not correctly set up, the Active Line Module Chassis-2
connected to the Active Interface Module Chassis-2 can be destroyed during switch-on.
• The pre-charging input circuit must be implemented according to the following circuit
Air-cooled chassis power units
Manual, 07/2019, 6SL3097-4AE00-0BP9
upstream of the fan power supply.
and the notes for dimensioning the various components.
Line-side power components
4.7 Active Interface Modules Chassis-2
119