Overview
The Allen-Bradley W55 is a thermal overload heater element engineered for motor circuit protection in industrial automation and control applications. This overload heater element has a current rating of 12.8–13.7 amps and is used for thermal overload relays, magnetic motor starters, and motor controls. The W55 is an eutectic alloy type overload relay heater for Bulletin 500 line starters that provides Class 20 operation and is recommended for general applications.
Key Features
- Eutectic alloy construction for reliable thermal response
- Class 20 trip protection rated for manual reset operation
- Full load current range of 12.8–13.8 amps across NEMA sizes 00–0, 1, and 2
- Type W heater configuration compatible with standard Bulletin 500 motor starters
- Compact, lightweight design (0.05 lbs) for easy installation and replacement
Technical Specifications
| Manufacturer | Allen-Bradley (Rockwell Automation) |
| Part Number | W55 |
| Product Type | Thermal Overload Heater Element |
| Heater Type | Type W, Eutectic Alloy |
| Trip Class | Class 20 |
| Reset Type | Manual |
| Current Rating @ Size 00–0 | 13.6 Amps |
| Current Rating @ Size 1 | 13.7 Amps |
| Current Rating @ Size 2 | 13.8 Amps |
| Full Load Amps Range | 12.8–13.8 A |
| Weight | 0.05 lbs |
| Material | Eutectic Alloy |
| Applicable Standard | NEMA Overload Relay Heater Element |
| Condition | New in Box |
Typical Applications
The Allen-Bradley W55 thermal overload heater is ideal for:
- General-purpose motor protection in industrial automation systems
- NEMA motor starters and magnetic motor controls
- Bulletin 500 line starter applications across NEMA frame sizes 00–0, 1, and 2
- OEM equipment manufacturing where standard overload relay protection is required
- Retrofit and replacement of worn or damaged heater elements in existing motor control circuits
Compatibility & Replacements
Compatible With
- Allen-Bradley Bulletin 500 magnetic motor starters
- NEMA sizes 00–0, 1, and 2 motor starter frames
- Thermal overload relay assemblies with Type W heater configuration
- Standard industrial motor control systems requiring Class 20 trip protection
Replaces / Drop-In Replacement For
The W55 is a direct replacement for original Allen-Bradley W55 heater elements in Bulletin 500 line starters. Verify compatibility with your system integrator before ordering to ensure proper NEMA size and current rating match.
Works With
- Allen-Bradley overload relay units for Bulletin 500 starters
- Manual or automatic motor starter control circuits
- Industrial automation systems with Class 20 trip protection requirements
- Standard NEMA motor control enclosures and equipment
