Application And Use; Areas Of Application And Criteria For Selection; Installation Guidelines - Siemens sirius System Manual

3RW3 semiconductor motor control unit

8.3 Application and use

8.3.1 Areas of application and criteria for selection

Applications
Cooling time

8.3.2 Installation guidelines

Stand-alone installa-
tion
8-18
The SIRIUS 3RW3 soft starters offer an alternative to star-delta starters (see
Section 8.2.4 for a comparison and the advantages).
The most important advantages are soft starting and soft coasting-down,
interruption-free switching without current spikes that could interfere with
the supply system, and compact dimensions.
Many drives that needed frequency converters in the past can be changed
to soft-start operation with the 3RW3, if the applications do not call for vari-
ations in speed.
Typical applications include, for example:
Conveyor belts, conveyor systems:
• Smooth starting
• Smooth slowing
• Use of better-value conveyor material
Rotary pumps, piston-type pumps
• Avoidance of pressure surges
• Extended service life of the piping system
Agitators, mixers:
• Reduced starting current
Fans:
• Less strain on gearing and drive belts
Note:
The cooling time must be taken into consideration in the starting frequency.
On account of the heat generated, certain installation guidelines must be
adhered to when combining 3RW30/31 soft starters with other SIRIUS
switching devices.
Stand-alone installation is when minimum vertical and lateral clearances
between the mounted devices are not violated. This applies both to indivi-
dual devices and complete load feeders.
The following minimum clearances must be adhered to in stand-alone instal-
lation (these minimum clearances depend on the frame size):
SIRIUS System Manual
GWA 4NEB 430 0999-02b