Description
The Schneider Electric (Square D) LR3D21L is a Class 20 thermal overload relay engineered to deliver dependable motor protection across a wide range of commercial and industrial HVAC applications. With an adjustable current range of 12A to 18A, this relay is designed to guard motors against damaging overload conditions, phase loss, and phase imbalance.
Product Overview
As part of the trusted Square D TeSys D series, the LR3D21L integrates seamlessly with compatible TeSys D contactors to form a complete motor starter assembly. Its Class 20 trip characteristic provides a longer tripping time, making it well suited for high-inertia loads and motors that require extended start-up periods — a common requirement in HVAC fan and pump motor applications.
Key Features
- Adjustable current setting range: 12A to 18A
- Class 20 trip class for high-inertia motor protection
- Provides protection against overload, phase loss, and phase imbalance
- Manual and automatic reset modes
- Integrated test and stop functions for simplified commissioning
- Designed for direct mounting on TeSys D series contactors
- Compact, DIN rail compatible design
- Auxiliary contacts included for remote signaling and control circuit integration
Application Suitability
The LR3D21L is ideal for protecting single-phase and three-phase motors in HVAC systems including air handlers, cooling towers, pumps, compressors, and exhaust fans. Its robust thermal bimetal technology ensures reliable, repeatable protection even in demanding environments.
Why Choose Schneider Electric (Square D)
Schneider Electric’s Square D brand is a globally recognized leader in electrical protection and control. The TeSys D overload relay line is known for its reliability, ease of installation, and compatibility within the broader TeSys ecosystem — making the LR3D21L a go-to choice for HVAC technicians and electrical contractors seeking proven motor protection solutions.
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