Overview
The Allen-Bradley W59 heater element is a thermal overload relay component designed for use in the Bulletin 500 line of motor starters and magnetic contactors. This Type W heater element is rated for 17.5–22.5 amps and is suitable for use with thermal overload relays, magnetic motor starters, and motor controls. The W59 provides Class 20 operation and is recommended for general applications. The eutectic alloy construction ensures reliable thermal protection and consistent trip characteristics across industrial environments.
Key Features
- Type W heater element for eutectic alloy thermal trip mechanism
- Class 20 rated operation for general-purpose applications
- Compatible with Bulletin 500 line starters (sizes 00–4)
- Direct replacement for legacy thermal overload cartridges
- NEMA-rated motor protection
- Rapid thermal response for fast overload detection
Technical Specifications
The Allen-Bradley W59 meets NEMA and industrial motor control standards. Current ratings include 18.9 amps @ size 00–1 and 19.1 amps @ size 2. Installation is straightforward in standard thermal overload relay sockets found in legacy and modern starter enclosures.
Typical Applications
- General-purpose industrial motors and pump drives
- Motor protection in Bulletin 509 starters and 592 overload relays
- Manufacturing and process control systems
- HVAC and facility equipment
- Replacement maintenance for legacy 500 line control systems
Compatibility & Replacements
Compatible With
- Allen-Bradley Bulletin 500 line motor starters (sizes 00–4)
- Allen-Bradley Bulletin 592 thermal overload relays
- Bulletin 509 magnetic starters
- Standard NEMA motor starter enclosures
Replaces / Drop-In Replacement For
- Legacy Type W heater elements in thermal overload relays
- Original equipment W59 cartridges
- Standard thermal trip cartridges rated 17.5–22.5 amps
Works With
- Thermal overload relay mechanisms (eutectic alloy type)
- NEMA Class 20 protection schemes
- Industrial motor control circuits
- Manual and automatic starter systems




