3Rt16 Capacitor-Switching Contactors For Switching Capacitors - Siemens sirius System Manual

3.3.4 3RT16 capacitor-switching contactors for switching capacitors

Field of application
Frame sizes
Auxiliary switch
Switching capacitors/
banks of capacitors
Precharging resistors
SIRIUS System Manual
GWA 4NEB 430 0999-02b
3 3RT1/3RH1 contactors
3RT16 capacitor-switching contactors are used to switch power capacitors
that are used in reactive-current compensation.
The capacitor-switching contactors are available in frame sizes S00 to S3
with the rating levels 12.5, 15 kvar, 25 kvar, and 50 kvar at 400 V.
S00
Figure 3-8: Capacitor-switching contactors (frame sizes S0 and S2)
The auxiliary switch block snapped onto the capacitor-switching contactor
contains three leading NO contacts and a normal NO contact that can be
assigned as you wish. A 2-pole auxiliary switch block can also be attached at
the side of the capacitor-switching contactors (variants: 2 NO contacts, 2 NC
contacts, or 1 NO + 1 NC contact).
A single capacitor can normally be switched on because the current is lim-
ited by the inductance of the upstream transformer and the cables. It is
more difficult to switch banks of capacitors (parallel connection of a capaci-
tor to capacitors already present) because the current is now only limited by
the low inductance of the connecting leads and the capacitors.
This problem is solved in the case of capacitor-switching contactors using
precharging resistors.
The precharging resistors are an integral part of the contactor in 3RT16
capacitor-switching contactors. They are switched on via leading auxiliary
contacts before the main contacts close. This results in damping down to
approximately 10 % of the undamped peak currents. Damping of peaks in
the making current prevents disturbances to the network.
3RT1/3RH1 contactors
S3
3-25