BE1-50/51, Self-Powered Time Overcurrent Relay

A single-phase self-powered, microprocessor-based time/instantaneous overcurrent relay that provides cost-saving overload and fault protection for generators, transformers, feeders, and motors. Available in multiple-rack, panel, and retrofit mounting options.

See the Relay Upgrade Experts Chart in the Technical Resources tab below to determine if a Basler relay can replace your older style relay.

Benefits
Manuals
Bulletins
Technical Resources
Applications
Case Studies

Benefits

Accurate, repeatable, and reliable operation.
No additional power source required since relays are self-powered from 50/60 Hz systems. Available in five- or one-amp CT secondary models.
Timings can be tailored to the application with multiple field-selectable curves.
Flexible pickup is continuously adjustable over a wide range.
Instantaneous protection can be set lower to provide more complete protection with a design that minimizes transient overreach.
Reduce arc flash hazards by applying a second independent instantaneous element available.
Models available to replicate decaying reset of electromechanical relay disks when current drops to zero.
Replace existing electromechanical relays with specifically-wired retrofit models.
Reduce CT costs with low sensing and supply burdens.
Reduce maintenance labor by eliminating the need for re-calibration.
Testing is easy with drawout construction for all models and in-case testability for most models.

Manuals

Instruction Manual
- BE1-50/51B Instruction Manual, Rev V, English (2.9MB)
- BE1-50/51M Instruction Manual, Rev U, English (3.7MB)
Instruction Manual (Plug-and-Play)
- BE1-50/51B (Model 122), Rev None (1MB)
  CO Retrofit Kit (5A) with extended instantaneous (50) time delay
- BE1-50/51B (Model 229), Rev F (2.5MB)
  SFC Retrofit Kit (5A)
- BE1-50/51B (Model 231), Rev D (3MB)
  IAC Retrofit Kit (5A) with 50 and 51 on shared terminals
- BE1-50/51B (Model 232), Rev C (3.1MB)
  IAC Replacement Relay (5A) with 50 and 51 on shared terminals
- BE1-50/51B (Model 233), Rev C (2.5MB)
  CO Replacement Relay (5A) with 50 and 51 on shared terminals
- BE1-50/51B (Model 240), Rev D (2.6MB)
  CO Retrofit Kit (5A) (FT-21 size)
- BE1-50/51B (Model 241), Rev E (2.6MB)
  CO Arc-Flash Retrofit Kit (5A) (FT-21 size)
- BE1-50/51B (Model 244), Rev F (2.7MB)
  CO Arc-Flash Replacement Relay (5A) (FT-11 size)
- BE1-50/51B (Model 252), Rev B (2.2MB)
  IAC Arc-Flash Retrofit Kit (5A), Hot Line Tag (HLT)
- BE1-50/51B (Model 253), Rev B (2.4MB)
  IAC Arc-Flash Retrofit Kit (5A), Hot Line Tag (HLT)
- BE1-50/51B (Model 254), Rev B (2.2MB)
  CO Arc-Flash Retrofit Kit (5A) (FT-11 size), Hot Line Tag (HLT)
- BE1-50/51B (Model 255), Rev C (2.8MB)
  CO Arc-Flash Retrofit Kit (5A) (FT-11 size), Hot Line Tag (HLT)
- BE1-50/51B (Model 256), Rev C (2.5MB)
  IAC Arc-Flash Retrofit Kit (5A), Hot Line Tag (HLT)
- BE1-50/51B (Model 257), Rev C (2.8MB)
  IAC Arc-Flash Retrofit Kit (5A), Hot Line Tag (HLT)
- BE1-50/51B (Models 121, 123), Rev C (2.6MB)
  Model 121: IAC Retrofit Kit (5A) with extended instantaneous (50) time delay, Model 123: IAC Replacement Relay (5A) with extended instantaneous (50) time delay
- BE1-50/51B (Models 214, 215, 223, 225), Rev S (3.5MB)
  Model 214: IAC Retrofit Kit (5A), Model 215: IAC66C Retrofit Kit (5A), Model 223: IAC Retrofit Kit (5A) with instantaneous (50) contact on terminals 9 and 10, Model 225: IAC Retrofit Kit (1A)
- BE1-50/51B (Models 218, 228), Rev L (2.8MB)
  Model 218: IAC Replacement Relay (5A), Model 228: IAC Replacement Relay (1A)
- BE1-50/51B (Models 219, 226, 258), Rev L (3MB)
  Model 219: CO Retrofit Kit (5A) (FT-11 size), Model 226: CO Retrofit Kit (1A) (FT-11 size), Model 258: CO Retrofit Kit (5A) (FT-11 size, 0.05 s instantaneous time delay option)
- BE1-50/51B (Models 230, 234, 239), Rev K (4.1MB)
  Model 230: IAC66K Retrofit Kit (5A), Model 234: IAC66K Retrofit Kit (1A), Model 239: IAC66K or IAC**A Arc-Flash Replacement Relay (5A)
- BE1-50/51B (Models 235, 236), Rev D (3MB)
  Model 235: CO Arc-Flash Retrofit Kit (5A) (FT-11 size), Model 236: CO Arc-Flash Retrofit Kit (1A) (FT-11 size)
- BE1-50/51B (Models 237, 238), Rev D (3.4MB)
  Model 237: IAC Arc-Flash Retrofit Kit (5A), Model 238: IAC Arc-Flash Retrofit Kit (1A)

Bulletins

Product Bulletin
- BE1-50/51B Bulletin, Rev 25, English (720.1KB)
  Time/Instantaneous Overcurrent Relay
- BE1-50/51B Retrofits Bulletin, Rev 23, English (679.7KB)
  BE1-50/51B Time/Instantaneous Overcurrent Relay Retrofit Kits
- BE1-50/51M Bulletin, Rev 18, English (797KB)
  Time/Instantaneous Overcurrent Relay
- Standards, Dimensions and Accessories, Rev 23, English (1.4MB)
  BE1 Protection Systems and Relays
Brochure
- Brochure: Power Systems Solutions - Proven Worldwide, English (5.9MB)
  Solutions for Excitation Systems, Protection Systems/Relays, Voltage Regulators, and Genset/Engine Controllers.
- Brochure: Power Systems Solutions - Proven Worldwide, Japanese (6.4MB)
  Solutions for Excitation Systems, Protection Systems/Relays, Voltage Regulators, and Genset/Engine Controllers.
Flyer
- Plug and Play Solutions (1.1MB)
  Plug and Play retrofits minimize cost and out-of-service time without the need for case replacement or rewiring.

Technical Resources

Application Guide
- Application Guide: Generator Protection (2.5MB)
  Simplify the process of selecting relays and relay systems to protect generators.
- Application Guide: Motor Protection (1.3MB)
  Overview of motor hazards and detection and protection options, plus typical setting-value range for BE1-11m.
- Application Guide: Transformer Protection (2.2MB)
  Simplify the process of selecting relays and relay systems to protect power transformers.
Retrofit Chart
- The Upgrade Experts — Plug-and-Play and Retrofit Relays (169KB)
Software Tool (spreadsheet)
- Spreadsheet: Time Current Characteristic Curve Calculator (187.5KB)
  Time current characteristic-curve calculator spreadsheet.
Technical Paper
- Technical Paper: A Review of System-Grounding Methods and Zero-Sequence Current Sources (1.1MB)
  Grounding methods, sources of ground current, ground-current flow in the power system, and how each impacts protective relaying.
- Technical Paper: A Survey of Cold Load Pickup Practices (1MB)
  Cold load pickup, the causes and effects.
- Technical Paper: Application of Islanding Protection for Industrial- and Commercial-Generators (990.9KB)
  Issues associated with the islanding of an industrial- or commercial-facility power system where a synchronous generator operates in parallel with the utility source.
- Technical Paper: Bus-Protective Relaying, Methods and Application (1.9MB)
  Application of bus-protective relaying, describing and comparing differences.
- Technical Paper: Choosing the Correct Transfer Switch (569.1KB)
  For effective ground-fault protection, transfer switch must be chosen at project beginning.
- Technical Paper: Current Transformer Errors and Transformer Inrush as Measured by Magnetic, Optical and other Unconventional CTs (1.4MB)
  Errors in secondary current for these primary current conditions determine when CTs are at risk, and show, using numerical analysis, the output of a saturated CT.
- Technical Paper: Distributive Generation and Interconnection: Protection, Monitoring, and Interconnection Opportunities (1.8MB)
  Paralleling a distributed-generation supply to an electric power system involves protection, monitoring and control of the interconnection.
- Technical Paper: Effects of Distributed Generation on Utility Protection Schemes (782.1KB)
  Addition of distributed generation to a distribution feeder can be minimized by having digital multifunction overcurrent with voltage-protection schemes.
- Technical Paper: Intertie Requirements for DGs Connected to Radial-Distribution Feeders (537.3KB)
  Proposed protection requirements for distributed generation connected to radial-distribution feeders.
- Technical Paper: Life Lessons from the Power System (1.1MB)
  Explores the basic principles of relay protection design and relay protection commissioning, while reflecting upon lessons learned.
- Technical Paper: Myths of Protecting the Distributed Resource To Electric Power System Interconnection (1.1MB)
  For the ideology of power-system protection, the myths described in this paper are better described as conditional truths rather than half-truths.
- Technical Paper: Protective Relaying Issues in Low-Voltage Systems as Addressed in the National Electric Code (1.6MB)
  Low Voltage (LV) design practices, as mentioned in the National Electric Code (NEC).
- Technical Paper: Protective Relaying Methods for Reducing Arc-Flash Energy (1MB)
  Arc flash standards/requirements and high-speed detection and operation techniques used to reduce arc-flash energy via protective relays.
- Technical Paper: Protective Relaying When Distributed Generation is Added to Your Circuit (874.4KB)
  Advantages of having numeric multifunction protection in place when distributed generation is added to a radial-distribution circuit.
- Technical Paper: Upgrading Intertie Protection to meet TX PU Standards (1MB)
  Utilizing multifunction relays as the sole means of protection, not only for the plant and its generation, but also for the utility.

Applications

Application Guide
- Application Guide: Generator Protection (2.5MB)
  Simplify the process of selecting relays and relay systems to protect generators.
- Application Guide: Motor Protection (1.3MB)
  Overview of motor hazards and detection and protection options, plus typical setting-value range for BE1-11m.
- Application Guide: Transformer Protection (2.2MB)
  Simplify the process of selecting relays and relay systems to protect power transformers.
Application Note
- Application Note: PC-5051B (481.7KB)
  Electromechanical overcurrent relay replacement made quick and easy.
- Application Note: PC-5051B02 (460.1KB)
  How to select the appropriate BE1-50/51B model for IAC and CO replacement.
- Application Note: PC-ARCFLASH2 (804.7KB)
  Helping electric utilities manage NESC 410.A.3 "Flame Retardant Clothing Requirement".
- Application Note: PC-CASES (1.1MB)
  Basler Electric cases and dimensions vs. older electromechanical relays.
- Application Note: PC-HLT (864.8KB)
  BE1-50/51B Self-Powered Overcurrent Retrofit with Hot Line Tag (HLT).
- Application Note: PC-IAC66K (431.9KB)
  Replacing IAC66K type relay.