Schneider Thermal Overload Relay LRD3359

Schneider Electric LRD3359 Thermal Overload Relay

Schneider Thermal Overload Relay LRD3359 — Heavy-Duty Motor Protection

The Schneider Thermal Overload Relay LRD3359 is a robust industrial protection device designed to safeguard medium-to-large three-phase motors against prolonged overcurrent, phase loss, and load imbalance. It is part of Schneider Electric’s trusted TeSys LRD range of thermal overload relays, commonly used in motor starter assemblies with contactors like LC1D80 and LC1D95 — ensuring dependable and precise protection in industrial, commercial, and manufacturing electrical systems.

The LRD3359 helps prevent motor damage by sensing excessive current and tripping before thermal stress causes winding failure or mechanical issues. Its rugged design and adjustable settings make it a preferred choice for control panels, production lines, and heavy machinery installations across Indian industries.

🔌 Key Features & Benefits

• Adjustable Current Range (48–65 A) – Fine-tune the relay to match the full-load current of your motor for accurate overload protection.

• Three-Pole Thermal Protection – Monitors all three phases to disconnect power when overload or imbalance is detected.

• Class 10A Trip Characteristic – Conforms to IEC 60947-4-1; tolerates short inrush currents while tripping reliably on sustained overloads.

• Phase Loss & Unbalance Detection – Helps prevent motor faults by reacting to abnormal phase conditions before damage occurs.

• Manual/Automatic Reset & Test Function – Offers flexibility in how relays reset after a trip; test button allows easy verification without powering down.

• Auxiliary Contacts (1NO + 1NC) – Suitable for signalling faults to control panels or automation systems.

• Secure Screw-Clamp Terminals – Ensures reliable electrical connections with vibration-resistant mounting.

• Direct Mount or Panel Mount – Can be installed directly under compatible contactors or mounted on DIN rail/panel for flexible integration.

⚙️ Why Choose the LRD3359 Overload Relay?

Motors in industrial environments often face heavy start-up currents, continuous duty cycles, and load variations that can cause prolonged overcurrent and thermal stress. The Schneider LRD3359 Thermal Overload Relay:

• Protects motors from overheating and damage

• Reduces unplanned downtime and repair costs

• Enhances system safety and reliability

• Integrates seamlessly into TeSys motor starter systems

This makes it ideal for plant-wide motor protection strategies, control panels, and automated systems.

📌 Typical Industrial Applications

• Motor starter assemblies with TeSys contactors

• Pumps, compressors, and conveyor drives

• HVAC and ventilation motors

• Industrial machinery and production equipment

• Power distribution panels requiring overload protection