Overview
The Allen-Bradley W55 is a NEMA-rated overload heater element manufactured by Rockwell Automation for thermal overload relay protection in industrial motor control applications. This Type W eutectic alloy heater element delivers Class 20 trip protection and is the standard choice for Bulletin 500 line starters requiring general-purpose motor overload protection.
Key Features
- Eutectic alloy construction for reliable thermal response and repeatability
- Class 20 operation—recommended for general industrial applications
- Type W designation compatible with standard 500 Line thermal overload relays
- Manual reset type for controlled circuit protection
- Compact, drop-in replacement design—no retrofit required
- Full Load Amp (FLA) ratings: Size 00-0 (13.6A), Size 1 (13.7A), Size 2 (13.8A)
Technical Specifications
- Part Number: W55
- Manufacturer: Allen-Bradley / Rockwell Automation
- Product Type: Heater Element (Overload Relay)
- Material: Eutectic Alloy
- Heater Type: Type W
- Trip Class: Class 20
- Reset Type: Manual
- Full Load Amps (FLA): 12.8–13.8 AMP (varies by size)
- Application: Bulletin 500 Line Starters
- Weight: 0.04–0.05 lbs
- Standard: NEMA / KC compliant
Typical Applications
The Allen-Bradley W55 heater element is ideal for:
- Thermal protection in magnetic motor starters and contactors
- General-purpose motor overload protection in industrial machinery
- Bulletin 500 line NEMA motor control systems
- Commercial HVAC, pump, compressor, and fan motor circuits
- Maintenance and replacement in existing 500 Line starter installations
Compatibility & Replacements
Compatible With
- Allen-Bradley Bulletin 500 Line thermal overload relays
- NEMA-rated magnetic motor starters (sizes 00 through 2)
- Industrial motor control systems requiring Class 20 protection
- Manual and automatic motor start circuits
- OEM equipment manufactured to Bulletin 500 Line standards
Replaces / Drop-In Replacement For
The W55 serves as a direct replacement for any Type W overload heater element in Bulletin 500 Line starters. Verify exact size and amperage rating with your system integrator or motor starter documentation before ordering to ensure proper protection coordination.
Works With
- Allen-Bradley Bulletin 500 Line thermal overload relays
- Standard NEMA-compliant motor control contactors
- Manual and semi-automatic motor starters
- Industrial circuit protection and relay systems
- Class 20 thermal protection applications per NEMA standards
