Product Overview
Allen-Bradley N56 Type N Heater for High-Current Motor Overload Relays
Thermal overload heater elements are precision-calibrated components used in Allen-Bradley overload relays and motor starters to protect electric motors from sustained overcurrent. The heater converts motor line current into heat that mirrors motor thermal behavior, providing inverse-time protection rather than instantaneous interruption. Correct selection is based on motor nameplate current and relay design, not horsepower alone, across single-phase / three-phase AC motor systems.
Product Condition
Unused, New Old Stock.
Product Overview
The Allen-Bradley N56 is a Type N thermal overload heater element from the legacy N-Series. It installs into compatible Allen-Bradley overload relays and magnetic motor starters that accept screw-in Type N heaters. During sustained overload conditions, the heater warms the relay’s internal bimetal or eutectic mechanism until the calibrated trip point is reached.
Key Features
- Allen-Bradley Type N thermal overload heater element
- Designed for compatible Allen-Bradley overload relays and motor starters
- Provides inverse-time motor overload protection, typically Class 20
- Heater selection value corresponds to a higher motor full-load current range, approximately 25 A
- Each N-number is electrically calibrated and not interchangeable
- Similar physical form factor across Type N heaters with different trip characteristics
- Part of the legacy N-Series used in NEMA motor control equipment
Applications
- Motor overload protection in magnetic motor starters
- General-purpose AC motor control circuits
- Medium to larger three-phase induction motors
- Higher-current motor applications in industrial equipment
- Maintenance of legacy Allen-Bradley NEMA starters
- Industrial control panel repair and refurbishment
Frequently Asked Questions
What does the N56 heater number represent?
The N56 designation identifies a specific thermal calibration tied to a defined motor full-load amp range. Heater size is selected using Rockwell Automation heater tables based on the motor nameplate FLA and application conditions.
Are Type N heaters interchangeable if they share the same form factor?
No. Although Type N heaters share a similar mounting style, each N-number has a different electrical calibration. Substituting heater sizes can result in nuisance tripping or inadequate motor protection.
How does the N56 compare to lower-numbered N-Series heaters?
The N56 is intended for significantly higher full-load current motors than models such as N32 or N18. In the same overload relay family, an N56 will trip at a higher sustained current.
What equipment is this heater designed to work with?
The N56 is designed for Allen-Bradley overload relays and magnetic motor starters that accept Type N heater elements, commonly found in legacy NEMA motor control assemblies.
You can maintain correct inverse-time motor protection in a legacy magnetic starter by installing this N56 Type N heater element into the existing overload relay block matched to the motor’s nameplate full-load current.
