PowerFlex SCR Bridge Bus Supply

Bulletin 20S SCR Bridge is a non-regenerative DC bus supply that supplies power to AC drives that have a common DC bus input. The supply converts incoming three-phase AC line voltage to a common DC bus voltage. You can configure this supply for stand-alone and master-slave applications.

Popular Resources/Quicklinks
PowerFlex SCR Bus Supply User Manual AC Drives Common Bus Configurations Application Guidelines


  • Six-pulse, full-wave, three-phase SCR bridge rectifier unit
  • Stand-alone and master-slave configurations (1000 A units only)
  • Built-in AC line and DC bus fuses (400 A and 600 A units)
  • Rectifier branch fuses, snubber circuit, and DC bus feedback fuses (1000 A units)
  • Over-temperature sensor located in the heat sink
  • RC snubber circuit for dampening and linearity of over-voltages

Product Selection


  • CE marked for all applicable directives
  • cULus
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Resource Publication Number Language
PowerFlex SCR Bus Supply User Manual 20S-UM001
AC Drives Common Bus Configurations Application Guidelines DRIVES-AT002
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Typical applications for the PowerFlex 20S Common Bus Power Supplies include:

  • Paper-Making Machines, Finishing Winders, Calendars, Rereelers
  • Metal-Rolling Mills, Slitters
  • Winders, Coaters, Calendars
  • Cranes

Drives Case Studies — View our case studies site to discover how customers have applied Allen-Bradley drives products in their applications.