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Entry type: Application example Entry ID: 62883732, Entry date: 03/21/2014

SINAMICS G: Line Contactor Control using the ON/OFF1 Command for G120

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  • Associated product(s)

SINAMICS G120 converters are designed to be directly connected to the line supply; neither a line nor input contactor is required. However, for some applications a line contactor may be necessary. 

A circuit is described, which allows the line contactor to be automatically opened and closed via a digital output contact in the converter Control Unit. The line contactor is switched using the ON/OFF1 command of the converter. This ON/OFF1 command can be received from every active converter command source. Optionally, the line contactor can be opened each time that the converter is switched-off, for example, as a result of a fault. No external components are required to implement the control. However, the permissible switching power (switching rating) of the digital output contact and the closing/holding power of the line contactor solenoid must be checked. It may be necessary to use an auxiliary contactor/relay.

This document does not include any specifications regarding how the

  • the converter is configured
  • the basic commissioning of the converter
  • higher-level controls for commissioning

It is assumed that readers have a basic knowledge of these topics.

This solution can be used for:

  • SINAMICS G120 with Control Units CU230P-2, CU240x-2, CU250S-2 and firmware from version 4.4
    (An external 24 V power supply must be connected to the converter via terminals 31 and 32 of the Control Unit)

This solution cannot be used for:

  • SINAMICS G120C with firmware release v4.4
  • SINAMICS G120 up to and including firmware release v3.x

For these drives, parameter p0857 cannot be accessed, with which the monitoring time for the DC link pre-charging can be set (i.e. extended).
As a result of the excessively low DC link voltage, the converter quickly goes into the "Fault" state when the ON/OFF1 command is issued.


Content of Downloads


Line Contactor Control using the ON/OFF1 Command for
62883732_MainContactorControl_v1_1_en.pdf ( 159 KB )

Further Information
For MICROMASTER 4 and SINAMICS G120 with Firmware (FW) V3.x please use the following link.



MICROMASTER, SINAMICS G: Controlling main contactor by using free function blocks (FFB) 22078212

Last Changes
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