Schneider Electric LR3D350 Thermal Iec Overload Relay

Product Description

The SCHNEIDER ELECTRIC LR3D350 is a thermal IEC overload relay rated for 37 to 50 amps and up to 690 volts AC. It protects motor starters and downstream equipment from sustained overcurrent conditions by tripping on excess heat generated by overload current. The relay uses thermal sensing to detect overload conditions and is classified as Trip Class 10A, meaning it trips within 10 seconds at six times the rated current. This device is installed by licensed electricians and industrial maintenance technicians working on motor control circuits in commercial and industrial applications.

The LR3D350 is designed for use in IEC motor starter assemblies where reliable overload protection is required. It is compatible with LC1D40A and LC1D65A contactors, making it a direct fit for those motor starter configurations. Typical installation scenarios include pump motor panels, HVAC equipment control panels, conveyor systems, and other three-phase motor-driven equipment in commercial or light industrial facilities. The Trip Class 10A rating suits applications with normal starting loads that do not require extended startup time.

Key Features

• Thermal sensing method detects overload current without electronic components
• Adjustable overload range from 37 to 50 amps to match motor full-load amperage
• Trip Class 10A for standard motor starting applications
• Rated for up to 690 volts AC for compatibility with international motor circuits
• Meets ATEX, CSA, UL 508, and EN/IEC 60947-4-1 certifications for broad compliance
• Direct mounting companion to LC1D40A and LC1D65A contactors

Compatibility

Designed for use with LC1D40A and LC1D65A IEC motor contactors as specified by the manufacturer.

Installation Notes

Installation should be performed by a qualified electrician in accordance with NEC requirements and applicable local codes. De-energize and lock out the motor control panel before installing or adjusting the overload relay. Set the overload current dial to match the motor nameplate full-load amperage before returning the circuit to service. Do not bypass or jumper the overload relay contacts during testing.