Overview
The Allen-Bradley W64 is a Type W eutectic alloy thermal overload heater element designed for use in Allen-Bradley Bulletin 500 line magnetic motor starters and thermal overload relay protection circuits. With a current rating of 27.2–36.9 amps, the W64 provides Class 20 trip protection suitable for general-purpose motor control applications. This heater element is part of Allen-Bradley’s standard overload relay lineup and is engineered to deliver predictable thermal protection across varying ambient temperature conditions.
Key Features
- Current Rating: 27.2–36.9 amps full load
- Type W Eutectic Alloy: Precise thermal response for reliable overload protection
- Trip Class 20: Recommended for general-purpose motor applications
- Manual Reset: Requires manual intervention after thermal trip event
- NEMA Compatibility: Works with Bulletin 500 line magnetic starters (Sizes 0–3)
- Ambient Temperature Compensation: Design accounts for temperature differentials between motor and controller locations
Technical Specifications
- Product Type: Thermal Overload Heater Element
- Manufacturer: Allen-Bradley / Rockwell Automation
- Model Number: W64
- Current Range: 27.2–36.9 amps
- Element Type: Eutectic Alloy (Type W)
- Trip Class: 20
- Reset Type: Manual
- Suitable Starter Sizes: NEMA 0, 1, 2, 3 (Bulletin 500)
- Weight: 0.05 lb (approx.)
- Standard: KC (Underwriters Laboratories)
- Condition: New in Box
Typical Applications
The W64 overload heater is used to protect three-phase AC squirrel-cage induction motors in:
- General industrial motor control circuits
- Pump and compressor starter applications
- Fan and blower motor protection
- Machine tool motor starters
- HVAC system motor controls
- Conveyor and material-handling systems
Proper heater element selection requires matching the motor’s full-load amperage (FLA) with the appropriate thermal element rating. Allen-Bradley selection tables (Bulletin 592) account for ambient temperature corrections to ensure that both the motor and starter are protected adequately.
Compatibility & Replacements
Compatible With
- Allen-Bradley Bulletin 500 line magnetic starters (Sizes 0, 1, 2, 3)
- Standard thermal overload relay protection circuits
- NEMA-rated motor control enclosures
- Class 20 thermal overload relay systems
Replaces / Drop-In Replacement For
- Previous-generation W64 thermal elements in Bulletin 500 overload relays
- OEM W64 elements in existing motor starter installations
Works With
- Allen-Bradley thermal overload relays (Bulletin 500 line)
- NEMA magnetic motor starters
- Class 20 overload trip protection systems
- Manual or automatic reset relay configurations
