The 3RA21404HD451NB3 is a SIRIUS compact starter from Siemens. These starters are designed for direct-on-line starting of three-phase asynchronous motors. They combine switching, overload protection, and short-circuit protection into a single compact unit, which simplifies wiring and reduces panel space.

Applications:

• Direct-on-line starting of three-phase motors
• Pumps
• Fans
• Compressors
• Conveyors
• General industrial machinery

Features:

• Compact design
• Integrated overload protection
• Integrated short-circuit protection
• Direct-on-line starting capability
• Screw-type terminals for easy wiring
• Robust and reliable performance
• SIRIUS modular system compatibility

Benefits:

• Reduced panel space requirements
• Simplified wiring and installation
• Improved motor protection
• Increased system reliability
• Reduced downtime
• Cost-effective solution

Additional Details:

The 3RA21404HD451NB3 typically includes a combination of a circuit breaker and a contactor. The overload protection is provided by a bimetallic strip or an electronic overload relay. The short-circuit protection is provided by the circuit breaker. The specific current rating and motor power rating will vary depending on the exact configuration. Consult the Siemens documentation for detailed specifications, including voltage ratings, current ratings, trip curves, and environmental conditions. The 'NB3' suffix may indicate specific options or configurations, such as the type of terminals or additional features.