Skip to content
Benshaw soft starters are designed from the ground up to perform dependably … even in the harshest industrial environments. We offer best-in-class solutions for continuous duty applications, hazardous locations/conditions, corrosive environments and high vibration operations.
Banner_Header_Industries_Mining
Benshaw provides a wide range of standard controls and drives for many industries, offering tailored solutions for even the most complex applications.
Banner_Header_Products_MVH2
Whether you need hands-on training, 24/7 troubleshooting, field service, or upgrade assistance, our experts are here to keep your operations running smoothly.
Banner_Header_Services_Field-Service
Benshaw has grown to become a recognized leader in the design, development and manufacture of mission critical motor controls and drives.
Banner_Header_Company_About
Benshaw's resources include an extensive document library, newsletter, FAQs, and case studies.
Banner_Header_Resources_Documents
Need help? Reach a Benshaw representative or local office for sales, service, or support. For urgent issues, use our technical support hotline.
Banner_Header_Contact_Representative
benshaw-hero-banner-2

RB2/RB3 Series Open Chassis Starters

Ratings from 208 - 575V up to 838A

Rugged Industrial Solid State Starters with Integral Bypass

Benshaw RB2/RB3 Series Solid State Starters combine the high performance MX2/MX3 motor control technology with a rugged, compact, integral bypass RB series power section.

The MX2 or MX3 technology provides users with a powerful group of programming parameters, designed for flexibility in across a wide range of industrial applications. Both MX2 and MX3 controls provide simple setup and commissioning via the Quick Start Menu.

The RB power section is a rugged, heavy duty solid state starter section designed with integral bypass contactor for a compact, efficient profile. The modular design includes separate poles for each phase for ease of maintenance.

UL-CUL-CC-CE-Certification-Logos

 

RB2 & RB3

Key Advantages

  • Modular power stack assembly for ease of maintenance
  • ModBus standard/other  Fieldbus optional
  • Multiple starting ramps  for various applications 
  • Integrated metering  system diagnostics 
  • Ethernet IP/TCP
  • Profibus
  • DeviceNet
  • Integral bypass contactor for efficient operation, eliminating the need for external fans
  • Integrated motor protection
  • Dual ramp capability for loaded/ unloaded applications
  • Power stack has multiple ratings for application flexibility

  • RB2 Starters
  • RB3 Starters

RB2 Open Chassis Soft Starters

The RB2 Open Chassis Soft Starter is a compact, simple to use soft starter with built-in motor protection, providing greater control in starting and stopping of three phase motors. The integral bypass contactor reduces the watt loss of the soft starter allowing RB2 Open Chassis Soft Starters to be mounted in non-vented enclosures.

Benshaw’s MX2 control technology (included with RB2 Open Chassis Soft Starters) provides basic motor protection with adjustable overload settings. MX2 control technology also provides user adjustable motor ramp profiles that can be tailored to the motor load, allowing for a smooth ramp of the motor, and adjustable voltage control deceleration suitable for pumping applications.

The RB power section is a rugged, heavy duty solid state starter section designed with integral bypass contactors for a compact, efficient profile. The modular design includes separate poles for each phase for ease of maintenance.

RB2 Open Chassis Soft Starters can be programmed using a board-mounted LED keypad, Modbus register mapping, or optional remote mount LCD keypad.

Key Advantages
  • Small, compact design
  • Modular power stack assembly for ease of maintenance
  • ModBus standard/other Fieldbus optional
  • Multiple starting ramps for various applications
  • Integrated metering system diagnostics
  • Integral bypass contactors for efficient operation, eliminating the need for external fans
  • Integrated motor protection
  • Dual ramp capability for loaded/unloaded applications
  • Power stack has multiple ratings for application flexibility

MX2 Control Highlights

MX2 control technology from Benshaw provides a powerful, flexible, intelligent low voltage motor control platform. MX2-based controls offer multiple, user selectable starting modes, an increased selection of configurable digital and analog I/Os, comprehensive built-in metering capabilities, unprecedented onboard protection and an easy-to-use, intuitive user interface.

The control board terminal configuration — coupled with programmable burden CT settings — makes Benshaw’s MX2 technology an excellent choice for a wide range of intelligent, soft start motor control applications. With more built-in starting modes … more built-in protection features … additional communications capabilities … improved noise immunity … a more complete user I/O and CE compliance, Benshaw’s MX2-based low voltage motor controls raise the bar for intelligent, low-cost, soft start motor control.

When you factor in our unique three-year factory warranty and 24/7 comprehensive technical support, we think you’ll find Benshaw’s MX2-based controls to be the best value on the planet.

Motor Protection Features
  • ANSI 19 – Reduced voltage start
  • ANSI 27 / 59 – Adjustable over/under voltage protection (Off or 1 to 40%, time 0.1 to 90 seconds in 0.1 second intervals, independent over and under voltage levels)
  • ANSI 37 – Undercurrent detection (Off or 5 to 100% and time 0.1 to 90.0 seconds in 0.1 second intervals)
  • ANSI 46 – Current imbalance detection (Off or 5 to 40%)
  • ANSI 47 – Phase rotation (selectable ABC, CBA, Insensitive, or Single Phase)
  • ANSI 48 – Adjustable up-to-speed / stall timer (1 to 900 seconds in 1 second intervals)
  • ANSI 50 – Instantaneous electronic overcurrent trip
  • ANSI 51 – Electronic motor overload (Off, class 1 to 40, separate starting and running curves available)
  • ANSI 51 – Overcurrent detection (Off or 50 to 800% and time 0.1 to 90.0 seconds in 0.1 second intervals)
  • ANSI 51G – Residual ground fault detection (Off or 5 to 100% of motor FLA)
  • ANSI 74 – Alarm relay output available
  • ANSI 81 – Over/under frequency
  • ANSI 86 – Overload lockout
  • Single phase protection
  • Shorted SCR detection
  • Mechanical jam

RB3 Open Chassis Soft Starters

The RB3 Open Chassis Soft Starter is a rugged compact, simple to use soft starter with built-in motor protection that gives you greater control in starting and stopping of three phase motors. The integral bypass contactor reduces the watt loss of the soft starter allowing RB3 Series Open Chassis Soft Starters to be mounted in non-vented enclosures.

Benshaw’s MX3 control technology (included with RB3 Series Open Chassis Soft Starters) provides advanced motor protection with adjustable overload setting and available RTD monitoring … eliminating the need for a third party motor protection relay. A real time clock with an event recorder (up to 99 events) is also included with the MX3 control technology, along with adjustable motor ramp profiles that can be tailored to the motor load (allowing for a smooth ramp of the motor) and adjustable voltage control deceleration suitable for use in pumping applications.

The RB power section is a rugged, heavy duty solid state starter section designed with integral bypass contactors for a compact, efficient profile. The modular design includes separate poles for each phase for ease of maintenance.

Benshaw’s RB3 Series Open Chassis Soft Starters can be programmed using the provided remote mount LCD keypad or Modbus register mapping.

Key Advantages
  • 8 user-configurable inputs
  • 2 fixed inputs for start and bypass confirm
  • 6 user-configurable relay outputs
  • 1 fixed output for bypass control
  • Real-time clock
  • Motor PTC input
  • Zero sequence ground fault
  • RTD module support
  • Event log (99 events)
  • Start per hour limiter
  • Back spin timer
  • Time between starts limiter
  • Zero speed switch input
  • Power outage ride through (PORT)
  • Power factor trip
  • Patented CYCLO control (0–40% speed)

MX3 Control Highlights

Benshaw’s next generation MX3 technology propels low voltage motor control to even greater levels of performance and functionality. With its real-time clock, enhanced programming capabilities, ease-of-use and a unique, flexible architecture — Benshaw’s MX3 controller delivers advanced motor control and protection with all of the rugged, dependable performance you’ve come to expect from the world leader in advanced controls and drives.

MX3 controllers, power components, software and sensors are all designed, built and tested to perform as an integrated control system, eliminating the coordination and performance problems inherent in other forms of reduced voltage starting. With more built-in features, more configurable options, greater expandability and a broader communications capability than any other motor control on the market, Benshaw’s next generation MX3 technology will shorten your commissioning times, improve motor performance and protection, enhance diagnostic capability and streamline electrical system monitoring and maintenance tasks.

Motor Protection Features
  • ANSI 14 – Speed switch and tachometer trip
  • ANSI 19 – Reduced voltage start
  • ANSI 27 / 59 – Adjustable over/under voltage protection (Off or 1 to 40%, time 0.1 to 90 seconds in 0.1 second intervals, independent over and under voltage levels)
  • ANSI 37 – Undercurrent detection (Off or 5 to 100% and time 0.1 to 90.0 seconds in 0.1 second intervals)
  • ANSI 38 – Bearing RTD / Other RTD / Open RTD alarm
  • ANSI 46 – Current imbalance detection (Off or 5 to 40%)
  • ANSI 47 – Phase rotation (selectable ABC, CBA, Insensitive, or Single Phase)
  • ANSI 48 – Adjustable up-to-speed / stall timer (1 to 900 seconds in 1 second intervals)
  • ANSI 49 – Status RTD
  • ANSI 50 – Instantaneous electronic overcurrent trip
  • ANSI 51 – Electronic motor overload (Off, class 1 to 40, separate starting and running curves available)
  • ANSI 51 – Overcurrent detection (Off or 50 to 800% and time 0.1 to 90.0 seconds in 0.1 second intervals)
  • ANSI 51G – Residual ground fault detection (Off or 5 to 100% of motor FLA) / zero sequence ground fault detection (Off, 0.1 – 25 amps)
  • ANSI 66 – Starts/hour and time between starts / restart block (backspin timer)
  • ANSI 74 – Alarm relay output available
  • ANSI 81 – Over/under frequency
  • ANSI 86 – Overload lockout
  • Single phase protection
  • Shorted SCR detection
  • Mechanical jam
Show more

Contact us to discuss your specific soft starter requirements with the Benshaw team