Allen-Bradley W43 Thermal Overload Relay Heater Element

Overview

The Allen-Bradley W43 is a Type W eutectic alloy thermal overload relay heater element engineered for reliable overload protection in motor control and magnetic starter applications. Providing Class 20 operation, it is a standard component in industrial automation systems and recommended for general-purpose motor protection across a wide range of starter sizes and current ratings.

Key Features

• Class 20 trip operation—precise thermal protection for standard industrial duty cycles
• Type W eutectic alloy construction—reliable, repeatable trip characteristics
• Compact design with minimal installation footprint
• Manual reset capability for controlled equipment restart
• Wide current range coverage (4.04–4.98 amps at Sizes 0/1/00; up to 1,035 amps at Size 8)
• Rated for 40°C ambient temperature operation

Technical Specifications

• Part Number: W43
• Heater Type: Type W, Eutectic Alloy
• Trip Class: Class 20
• Current Rating (Primary): 4.04–4.98 amps (Sizes 0/1/00, 24A, 32A, 40A)
• Current Rating (Size 5): 207–254 amps
• Current Rating (Size 7): 690–860 amps
• Current Rating (Size 8): 1,035 amps
• Reset Type: Manual
• Ambient Temperature: 40°C maximum
• Weight: 0.02–0.05 lbs
• Standard: KC (NEMA)
• Condition: New in Box

Typical Applications

• Motor control circuits with magnetic starters
• Thermal overload relay protection systems
• Industrial automation and process control
• NEMA-rated motor starter assemblies
• General-purpose motor protection (Classes A, B, C, D)

Compatibility & Replacements

Compatible With

• Allen-Bradley Bulletin 500 line starters
• Allen-Bradley Bulletin 100 motor control centers
• Allen-Bradley Bulletin 609 modular starters
• Allen-Bradley Bulletin 1200 soft starters
• Standard NEMA thermal overload relay bases and assem­blies
• Magnetic motor starters with Type W heater slots

Replaces / Drop-In Replacement For

The W43 is the standard Type W heater element for Allen-Bradley Bulletin 500 line starters in the current rating range specified. Verify your exact starter model and current rating before ordering to ensure compatibility.

Works With

• Allen-Bradley Overload Relay Blocks and Bases
• Rockwell Automation motor control products
• NEMA-compliant motor protection schemes
• Class 20 thermal protection circuits