Semiconductor soft starter 3RW3 8.3 Application and use 8.3.1 Application areas and selection criteria The SIRIUS soft starters 3RW3 offer an alternative to star-delta starters (see Chapter 8.2.4 for a comparison and advantages The most important advantages are soft starting and coasting, interruption- free changeover without current spikes placing a burden on the line and compact dimensions. Many drives that previously could only be operated with frequency convert- ers can be converted to soft starter operation with the 3RW3, provided no speed adjustment is necessary Applications Applications can be, for example: Conveyor belts, transport systems:
Jolt-free starting Jolt-free deceleration, Use of lower-cost belt material Centrifugal pumps, piston pumps Avoidance of pressure surges Prolonged useful life of the piping system Agitators, mixers: Reduced starting current Fans: Gentle operation of gears and V-belts Cooling time Note: The cooling time must be taken into account when considering the duty cycle! 8.3.2 Assembly specifications Owing to heat development, certain assembly specifications have to be observed when combining soft starters 3RW30/31 with other SIRIUS 3R switching devices. Rev. 08/99 8-17