8 3RW3 semiconductor motor control unit (soft starter) - Siemens ...
8 3RW3 semiconductor motor control unit (soft starter) - Siemens ...
8 3RW3 semiconductor motor control unit (soft starter) - Siemens ...
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<strong>3RW3</strong> <strong>semiconductor</strong> <strong>motor</strong> <strong>control</strong> <strong>unit</strong><br />
8.3 Application and use<br />
8.3.1 Areas of application and criteria for selection<br />
The SIRIUS <strong>3RW3</strong> <strong>soft</strong> <strong>starter</strong>s offer an alternative to star-delta <strong>starter</strong>s (see<br />
Section 8.2.4 for a comparison and the advantages).<br />
The most important advantages are <strong>soft</strong> starting and <strong>soft</strong> coasting-down,<br />
interruption-free switching without current spikes that could interfere with<br />
the supply system, and compact dimensions.<br />
Many drives that needed frequency converters in the past can be changed<br />
to <strong>soft</strong>-start operation with the <strong>3RW3</strong>, if the applications do not call for variations<br />
in speed.<br />
Applications<br />
Cooling time<br />
Typical applications include, for example:<br />
Conveyor belts, conveyor systems:<br />
• Smooth starting<br />
• Smooth slowing<br />
• Use of better-value conveyor material<br />
Rotary pumps, piston-type pumps<br />
• Avoidance of pressure surges<br />
• Extended service life of the piping system<br />
Agitators, mixers:<br />
• Reduced starting current<br />
Fans:<br />
• Less strain on gearing and drive belts<br />
Note<br />
The cooling time must be taken into consideration in the starting frequency.<br />
8.3.2 Installation guidelines<br />
On account of the heat generated, certain installation guidelines must be<br />
adhered to when combining <strong>3RW3</strong>0/31 <strong>soft</strong> <strong>starter</strong>s with other SIRIUS<br />
switching devices.<br />
Stand-alone installation<br />
Stand-alone installation is when minimum vertical and lateral clearances<br />
between the mounted devices are not violated. This applies both to individual<br />
devices and complete load feeders.<br />
The following minimum clearances must be adhered to in stand-alone installation<br />
(these minimum clearances depend on the frame size):<br />
SIRIUS System Manual<br />
8-18 GWA 4NEB 430 0999-02c
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