3RW5055-06AB14- Siemens Size 6 Soft Starter

3RW5055-06AB14- Siemens Size 6 Soft Starter

When a motor starts too hard, everything around it feels it—belts, gears, and even your power system. The Siemens 3RW5055-06AB14 SIRIUS soft starter is built to take that edge off. It brings motors up to speed gradually, cutting down on sudden jolts and helping your equipment last longer without constant maintenance.

This model handles 200–480V applications with a rated current of 143A, making it a solid fit for many common industrial setups. Once the motor is running, the built-in bypass takes over to keep things efficient and reduce heat inside your panel. You can also adjust how aggressively the motor starts, thanks to flexible current limiting and ramp settings. It’s straightforward to install, easy to work into existing systems, and doesn’t require a lot of extra components to get reliable protection in place.

It’s not flashy—and that’s a good thing. It’s designed to work quietly in the background, keeping your operation steady and your equipment protected.

Key Features and Benefits

• Smooth start and stop helps reduce wear on motors and connected equipment
• Built-in bypass improves efficiency during normal operation
• Adjustable current limiting (130% to 700%) for better control over startup
• Voltage ramp settings allow gradual acceleration and deceleration
• Integrated electronic motor overload protection
• Analog output (4–20 mA or 0–10 V) for monitoring
• Compact size makes panel installation easier
• Compatible with common industrial communication modules
• Designed for dependable use in demanding environments

Technical Specifications

• Manufacturer: Siemens
  
• Product Family: SIRIUS 3RW50 Soft Starters
  
• Catalog Number: 3RW5055-06AB14
  
• Operating Voltage: 200–480 V AC
  
• Control Voltage: 110–250 V AC (50/60 Hz)
  
• Rated Operational Current: 143 A (at 40°C)
  
• Motor Power Rating: Up to 75 kW at 400 V
  
• Frequency: 50/60 Hz
  
• Start Ramp Time: 0–20 seconds
  
• Ramp-Down Time: 0–20 seconds
  
• Current Limiting Range: 130%–700%
  
• Analog Output: 4–20 mA (default), configurable to 0–10 V
  
• Number of Phases Controlled: 2
  
• Dimensions: 198 mm (H) x 120 mm (W) x 249 mm (D)
  
• Weight: Approx. 3.98 kg
  
• Connection Type: Screw terminals (control), busbar (power)
  

Material Compliance and Certifications

• CE marked
• UL and CSA approved
• RoHS compliant (since 2019)
• REACH compliant
• WEEE compliant
• Meets IEC 60947-4-2 standards
• ATEX, IECEx, and UKEX certified for applicable environments

Where It Works Best

• Pumps where controlled startup helps avoid pressure spikes
• Fans and blowers that need steady acceleration
• Compressors to reduce strain during startup
• Conveyor systems where gradual starts protect materials
• HVAC systems requiring consistent motor control