Overview
The Square D A11.9 overload relay thermal unit is a critical component in motor control and protection circuits. Designed for use with thermal overload relays and magnetic motor starters, this thermal unit provides reliable overload protection by interrupting motor circuits when excessive current is detected. The A11.9 is rated for 7.71–8.81 amps full load amperage (FLA), making it ideal for small to medium AC induction motors in industrial automation applications.
Key Features
- Thermal sensing technology for accurate overload detection and motor protection
- Type A heater element compatible with Square D magnetic starters and motor control equipment
- FLA rating of 7.71–8.81 amps for appropriate motor sizing and protection coordination
- Lot of 2 units—economical replacement or spare inventory for multi-starter installations
- New in box condition, tested and ready for immediate installation
Technical Specifications
- Manufacturer: Square D
- Model Number: A11.9
- Type: Thermal Overload Heater Element (Type A)
- FLA Rating: 7.71–8.81 amps
- Application: Use with thermal overload relays, magnetic motor starters, and motor control equipment
- Quantity: Lot of 2
- Condition: New in Box
- Ambient Operating Temperature: 40°C rated (standard industrial ambient)
Typical Applications
The Square D A11.9 thermal unit is commonly used in:
- AC induction motor overload protection circuits
- NEMA-compliant magnetic motor starters (Class 8000 and similar)
- Industrial machine tool control systems and conveyor drives
- Pump, fan, and compressor motor control systems
- Replacement or spare inventory for maintenance and retrofit applications
Compatibility & Replacements
Compatible With
- Square D magnetic motor starters (Class 8000 series and compatible models)
- Square D thermal overload relay assemblies
- Standard three-phase AC induction motors rated 7.71–8.81 amps
- Motor control systems requiring NEMA-rated overload protection
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering to confirm this unit is suitable for your specific motor starter and application. Square D A Series thermal units are application-specific; proper FLA matching is critical for safe operation.
Works With
- Square D Class 8000 and Class 8501 magnetic motor starters
- Square D thermal overload relay assemblies and motor control enclosures
- Standard three-phase AC motor control circuits and protection schemes
