Siemens is launching a new soft starter from the Sirius series

Siemens Smart Infrastructure has expanded its soft starter portfolio for engines, launching the Sirius 3RW55 Failsafe and Sirius 3RW50. Soft starters provide protection for electric motors used in industry and infrastructure, during commissioning and shutdown. Sirius 3RW55 Failsafe are the first to have an integrated Safe Torque off (STO) function.

As stated in the safety standards, the protective function for electric drive systems ensures that the energy that creates torque stops working when the motors are switched off, thus preventing unwanted restarts. Control panel manufacturers no longer have to use multiple separate components to perform this function.

Sirius 3RW55 Failsafe are suitable for starting and stopping high-power three-phase (400V) motors with a nominal power of 5.5–560 KW. All switching operations can be controlled via an integrated human-machine interface. Additional communication modules offer complete diagnostics, statistics and measurement values ​​for the automation system.

Sirius 3RW50 devices cover a power range of 75–315 KW, for three-phase motors and are designed for standard applications. Additional functions can be installed via optional communication modules. The integrated soft torque function helps prevent excessive surges when starting and reduces mechanical loads when starting and stopping the motor. For this reason, these actuators are suitable for installation on pumps. They are ATEX and IECEx certified and can be applied in potentially explosive areas, for example, at airports or gas stations, where kerosene and gasoline are pumped.

All soft starter motors from the Siemens Sirius 3RW5 portfolio have built-in parameterization functions, a current flow limitation system with motor overload protection and a pump start and stop system. They can be integrated into the TIA portal and fully configured. Thanks to a number of certificates and approvals, which are in accordance with the International Electro technical Commission (IEC), Canadian Standards Association (CSA), these devices can be used worldwide.