Operating instructions

Introduction
MICROMASTER 420 / 440 – DC link coupling between several
Frequency inverters
4 Operation with only one supply frequency inverter
With this configuration, only one frequency inverter is connected to the line
supply and one or several frequency inverters is/are connected to the
supply inverter through the DC link. This then provides the energy for the
frequency inverters coupled at the DC link.
A&D SD Page 6/32
Copyright © Siemens AG 2005 All rights reserved
Line fuses
Line
contactor
Line reactor
Inverter
M
3 ~
Motor
M
3 ~
M
3 ~
Motor Motor
DC link fuses
MM440
30kW
MM440
1,5kW
MM420
1,5kW
Braking resistor
3-ph. 200-240V AC 50/60Hz
3-ph. 380-480V AC 50/60Hz
L1
L2
L3
PE
DC link fuses
PE PE PE
PEPEPE
Fig. 2-1: Block diagram of the DC link coupling with one supply inverter -
example for operation with a three-phase line supply