Enclosed Soft Starters

Our Enclosed SMC-3, SMC Flex, and SMC-50 soft starters are available as non-combination, combination fused disconnect, or combination circuit breaker starters. Enclosed soft starters may be fully customized with a wide variety of factory-installed options and are pre-engineered for quick factory lead times.

Enclosed Soft Starters
  • Overview
  • What's New
  • Product Selection
  • Specifications
  • Documentation
  • Resources

Product Comparison



SMC Flex


True 3-phase control Yes Yes Yes
Bypass Internal Internal External or Internal
Protection and diagnostics Basic Advanced Industry leading
Start/stop modes 5 9 17
Enclosure type
1/12/4 or 3R 1/12/4 or 3R 1/12/4 or 3R
Factory-installed communication modules (optional)
None RS-485, DeviceNet™, Ethernet/IP, ControlNet™, ProfiBUS RS-485, DeviceNet™, Ethernet/IP, ControlNet™, ProfiBUS
Voltage range
200...575V AC 200...575V AC 200...575V AC
Control voltage
100...240V AC 100...240V AC 100...240V AC
Option offering and customization
Moderate Extensive Extensive
Customization through modified standards Yes Yes Yes

Additional Information

  • Enhancements to Industrial Control Panels — We offer a wide range of packaged components, from high-availability standard enclosed motor starters to full customized industrial control panels. Watch Jeff Kilburn, Rockwell Automation, share some of the latest enhancements that include snap-together wiring technology and custom solutions to meet the unique challenges of OEMs and end users.
  • Our Industrial Automation and Control solutions help you build the most efficient industrial automation system to meet your needs.

SMC-50 Soft Starters Now Available with Internal Bypass

This new offering combines the advanced functionality of the SMC™-50 control platform with the energy savings capabilities of an internal bypass power structure. After the motor has been started and reaches full speed, the controller closes the internal bypass contactors which increases energy efficiency and reduces heat output. This results in:

  • Reduced enclosure size
  • Reduced cost, avoiding the need for external bypass contactors

The SMC-50 fully solid-state unit continues to be available with normal and heavy duty ratings for customer flexibility in difficult and demanding applications.

To view commonly ordered and quickly available products, use the Product Configuration Assistant for our complete product offerings.


  • cULus Listed (Open Type) (File No. E96956, Guides NMFT, NMFT7)
  • CSA Certified (File No. LR 1234)
  • CE Marked (Open Type) per EMC and Low Voltage Directive
  • CCC Certified

Product Certifications

Certifications apply when product is marked. See our Product Certification site for Declarations of Conformity, certificates and other certification details.

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Product Certifications

Certifications apply when product is marked. See our Product Certification site for Declarations of Conformity, certificates and other certification details.

Configuration & Selection Tools

  • CrossWorks — Convert competitive catalog numbers to similar Allen-Bradley® products.
  • ProposalWorks — Build complete quotes and proposals.

Other Resources

  • Firmware — Obtain firmware for your SMC Soft Starters from the Product Compatibility & Download Center.
  • Procurement Specifications — Visit our online resource to find the procurement specifications for this product.
  • SMC Estimation Wizard — Obtain a more advanced analysis of both the device and the system.
  • SMC Thermal Wizard — Conduct simple thermal analysis and selection of an SMC product for a given application.
  • Knowledgebase — Visit our online resource for technical information, support chat and forums, software updates, and product safety advisories/notices.