Overview
The Allen-Bradley W59 is a Type W eutectic alloy thermal overload heater element engineered for motor overload protection in Rockwell Automation’s Bulletin 500 Line motor starters and related NEMA equipment. Providing Class 20 operation, the W59 is the industry standard for general-purpose motor control applications requiring dependable thermal protection against overload conditions.
Key Features
- Type W eutectic alloy construction for consistent, repeatable trip curves
- Class 20 operation suitable for general industrial applications
- Manual reset design for controlled motor re-engagement
- Compact, drop-in replacement heater element
- Rated for full-load amp ratings from 18.9 A (Size 00-1) to 19.1 A (Size 2)
- Authentic Rockwell Automation / Allen-Bradley manufacture
Technical Specifications
- Part Number: W59
- Manufacturer: Allen-Bradley / Rockwell Automation
- Heater Type: Type W, Eutectic Alloy
- Trip Class: Class 20
- Reset Type: Manual
- Full Load Amp Rating (Size 00-1): 18.9 A
- Full Load Amp Rating (Size 2): 19.1 A
- Application Line: Bulletin 500 Line Starters
- Weight: 0.03-0.04 lbs
- Standards: NEMA Overload Relay Heater Element
Typical Applications
The Allen-Bradley W59 heater element is specified for:
- Bulletin 509 motor starters and contactor protection blocks
- Bulletin 592 overload relay modules
- Three-phase induction motor protection in HVAC, pump, compressor, and fan applications
- Industrial control systems where Class 20 trip curves match motor locked-rotor time ratings
- Retrofit and maintenance of legacy 500 Line motor control centers
Compatibility & Replacements
Compatible With
- Bulletin 500 Line Motor Starters (509, 509-BOD, 509-BOP)
- Bulletin 592 Overload Relay modules
- Type W heater sockets and thermal relay blocks designed for Size 0, 1, and 2 frames
- NEMA-style 3-phase motor control equipment
- Ambient temperature operation: standard industrial 40°C reference rating
Replaces / Drop-In Replacement For
The W59 is the direct replacement heater element for any Bulletin 500 or 509 motor starter or 592 overload relay originally equipped with a W59 heater unit. Verify heater cavity dimensions and amp rating match your specific motor nameplate FLA before ordering. Refer to Rockwell Automation selection tables for proper W-series heater sizing.
Works With
- Rockwell Automation legacy motor control systems
- NEMA standards for overload relay heater elements
- Ambient temperature compensation to 40°C per NEMA guidelines
- Mechanical reset architecture compatible with manual and electromechanical contactor blocks
- No software or firmware required (passive thermal element)
