Overview
The Allen-Bradley W64 is a eutectic alloy thermal overload relay heater element designed to protect three-phase AC squirrel cage and wound rotor motors in industrial automation and control applications. Type W heater elements are the Allen-Bradley standard for 500 Line starters, offering proven reliability in motor protection circuits. The W64 is selected when motor full-load current falls between 28.0 A and 30.0 A and is commonly paired with thermal overload relays in magnetic motor starter assemblies.
Key Features
- Eutectic alloy construction for consistent, temperature-compensated trip response
- Class 20 trip rating—trips in 20 seconds or less at 600% of rated current per NEMA ICS 2-222
- Manual reset design, standard KC marking
- Current rating: 27.2–36.9 amps (nominal 30.0 A)
- Proven compatibility with Bulletin 500 Line starters, all sizes
- Temperature-compensating design accounts for ambient conditions at motor and starter locations
Technical Specifications
- Current Rating: 27.2–36.9 A
- Heater Type: Eutectic Alloy
- Trip Class: Class 20 (NEMA)
- Element Type: Type W
- Reset Type: Manual
- Standard Marking: KC
- Bulletin Series: 500 Line Starters
- Application: NEMA Overload Relay (thermal)
- Weight: 0.05 lb
- Condition: New in Box
Typical Applications
The Allen-Bradley W64 heater element is recommended for general-purpose motor protection in:
- Three-phase AC motor starters (NEMA Sizes 0–3)
- Magnetic motor controllers protecting motors up to approximately 25–30 hp at 460 V
- Continuous-duty industrial processes where consistent overload response is critical
- Manufacturing equipment, conveyor systems, pump motors, and similar applications
- Industrial automation cabinets and control panels
For applications requiring Class 10 (fast-trip) protection, substitute Type J heater elements. For Class 30 (slow-trip) protection, use Type WL heater elements—change the “W” to “WL” in the selection table.
Compatibility & Replacements
Compatible With
- Allen-Bradley Bulletin 500 Line motor starters (all sizes)
- Thermal overload relays using Type W heater elements
- NEMA-rated magnetic motor starters
- Three-phase AC motor control circuits
- Motor protection relays with eutectic alloy design
Replaces / Drop-In Replacement For
- Other Type W heater elements in the 27.2–36.9 A range (verify exact heater element number from motor FLA and ambient temperature tables)
- Direct replacement for original W64 units in 500 Line assemblies
- Predecessor or equivalent units in legacy Bulletin 500 starters
Works With
- Allen-Bradley 500 Line overload relay blocks and thermal elements
- NEMA-compliant motor control standards (ICS 2-222 Class 20)
- Magnetic contactor assemblies from Allen-Bradley and compatible manufacturers
- Manual or semi-automatic motor starter frames
- Standard industrial AC power distribution (50/60 Hz)
