Overview
The Allen-Bradley W55 is a Type W thermal overload heater element designed for Bulletin 500 line starters and motor control applications. This eutectic alloy overload relay element provides Class 20 trip characteristics and is recommended for general industrial motor protection across NEMA sizes 00–2. The W55 delivers reliable thermal cutout when motor current exceeds safe operating limits, preventing thermal damage and equipment failure.
Key Features
- Eutectic alloy thermal element—consistent, repeatable trip performance
- Class 20 protection (12.8–13.8 amps) suitable for standard applications
- Compatible with Bulletin 500 line starters and magnetic motor starters
- Manual reset type—operator control over restart
- Compact, lightweight design (0.04–0.05 lbs) for panel-mount integration
Technical Specifications
- Full Load Current Rating: 12.8–13.8 Amps (13.6 A @ Size 00–0, 13.7 A @ Size 1, 13.8 A @ Size 2)
- Element Type: Type W, Eutectic Alloy
- Trip Class: Class 20
- Reset Type: Manual
- Bulletin Compatibility: 500 Line Starters
- Weight: 0.04–0.05 lbs
- Material: Eutectic Alloy
- Application Standard: NEMA (National Electrical Manufacturers Association)
Typical Applications
- Thermal overload protection in AC induction motor starters
- Magnetic motor starter protection (NEMA Sizes 00 through 2)
- General-purpose industrial motor control circuits
- OEM equipment requiring Class 20 overload characteristics
- Replacement element in existing Bulletin 500 line starter systems
Compatibility & Replacements
Compatible With
- Allen-Bradley Bulletin 500 line starters
- Thermal overload relays with Type W element sockets
- NEMA motor starter configurations (Size 00 through Size 2)
- Magnetic motor starter assemblies requiring Class 20 protection
- AC induction motor control circuits (general applications)
Replaces / Drop-In Replacement For
- Original equipment W55 heater elements in Bulletin 500 starters
- OEM thermal overload elements rated 12.8–13.8 amps, Class 20
- Verify compatibility with your system integrator before ordering
Works With
- Bulletin 500 overload relay assemblies
- NEMA-rated motor starter enclosures
- Manual motor control centers (MMCCs)
- Programmable controllers using auxiliary contacts for fault signaling (when relay module is integrated)
