Siemens SINAMICS PERFECT HARMONY GH150 6SL3826, Operating Instructions Manual

Page: 36 / 136

3.7.6 Precharging
The power cell capacitors must be precharged in order to avoid overcurrents and temporary
overvoltage conditions in the DC link when connecting the line supply. The DC link is
precharged via the auxiliary supply.
The precharging circuit comprises the following components:
● Precharging transformer
● Diode bridge
● Contactor for switching on and off
● Drive circuit breaker
● Low-voltage drives
Detailed information about interconnecting the precharging components is provided in the
circuit manual. The component mounting locations are provided in the layout diagram.
3.7.7 Actual value sensing
The actual value sensing is used to measure voltages and currents. The voltages are
measured using AVT combination modules, whose measuring resistors are connected in
series. The currents are measured using electronic LEM current transformers and AVT
combination modules.
AVT combination modules are separated and isolated from circuits that can be touched using
a transformer. The AVT combination modules convert analog signals into digital signals. They
transfer signals to the Power Stack Adapter (PSA) via fiber-optic cables.
Detailed information about interconnecting the actual value sensing modules is provided in the
circuit manual. The component mounting locations are provided in the layout diagram.
See also
Replacing the AVT combination module (Page 106)
Replacing the current transformer (Page 107)
3.7.8 Power supply (for ≥42 cells)
3.7.8.1 Field of application
The common power supply is an AC/AC converter that converts an alternating voltage into a
square-wave voltage.
The specified input voltage is 230 V AC ±20 %, and an additional transformer is added, if a
control voltage of 120 V AC is required.
Description
3.7 Components
SINAMICS PERFECT HARMONY GH150 6SL3826
36
Operating Instructions 05/2020