Overview
The Allen-Bradley W51 overload relay heater element is a NEMA-standard thermal protection component for industrial motor control systems. Class 20 operation makes it suitable for general applications where standard motor protection is required. This eutectic alloy heater element mounts directly into thermal overload relays and magnetic motor starters, providing automatic trip protection against sustained overcurrent conditions.
Key Features
- Eutectic Alloy Construction: Reliable thermal sensing and trip characteristic for consistent motor protection
- Class 20 Trip Rating: General-purpose protection standard for most industrial motor applications
- Type W Heater Element: Designed for Bulletin 500 and related line starters
- NEMA Compliance: Meets NEMA standards for overload relay heater elements
- Manual Reset Option: Available with manual reset configuration for safety-critical applications
- Drop-In Replacement: Direct replacement for existing W51 units without modification
Technical Specifications
- Current Rating: 8.95–9.32 amperes (Class 20)
- Element Type: Type W eutectic alloy heater
- Trip Class: Class 20
- Thermal Relay Type: Eutectic overload relay
- Reset Type: Manual
- Standard: KC (NEMA)
- Weight: 0.04 lb
- UPC: 781180154263
Typical Applications
The W51 heater element is used in:
- General-purpose AC induction motors (1/2 to 100+ hp)
- Bulletin 500 and 509 line starters with thermal overload relays
- Magnetic motor control centers and soft starters
- Industrial conveyor and pump applications
- Process automation and assembly equipment
- HVAC and refrigeration motor protection systems
Compatibility & Replacements
Compatible With
- Bulletin 500 line starters and overload relays
- Bulletin 509 thermal overload relays
- Bulletin 100 and 1200 line motor starters
- Allen-Bradley magnetic motor control centers
- NEMA-standard thermal overload relay housings
- Most major-brand NEMA motor starters (verify dimensions and contact configuration)
Replaces / Drop-In Replacement For
The W51 directly replaces existing W51 heater elements in thermal overload relays. For specific current ratings and starter models, consult the heater selection table in the Allen-Bradley Bulletin 592 technical data sheet or your system documentation. Verify compatibility with your system integrator before ordering if replacing units in unfamiliar equipment.
Works With
- Allen-Bradley thermal overload relay coils and contacts
- NEMA standard eutectic alloy overload relay elements
- Type W heater element retainers and mounting fixtures
- AC magnetic motor starter contactors
