Schneider Thermal Overload Relay LRD03

Schneider Electric LRD03 Overload Relay

Reliable Thermal Protection for Small Three-Phase Motors**

The Schneider Thermal Overload Relay LRD03 is a compact and dependable motor protection device from Schneider Electric’s TeSys LRD series, engineered to provide precise thermal overload safeguarding for small three-phase motors. With an adjustable current range and essential safety features, this relay is ideal for motor starter assemblies, control panels, and industrial electrical systems across India.

🔌 What Is the Schneider LRD03 Thermal Overload Relay?

The LRD03 is a three-pole thermal overload relay designed to monitor the current in all three phases of a motor circuit and disconnect power when sustained overloads or abnormal phase conditions occur, protecting motors from overheating and associated damage. It features an adjustable current protection range of 0.25 – 0.4 A, making it especially suited for small three-phase motors up to ~0.09 kW at 400 V AC.

This relay uses a Class 10A trip characteristic to balance tolerance for typical motor start-up currents with dependable response during prolonged overloads — meeting standard IEC motor protection norms.

🛠️ Key Features & Benefits

• Adjustable Protection Range (0.25 – 0.4 A): Tailor overload protection precisely to your motor’s full-load current.

• Class 10A Trip Curve: Designed to tolerate normal start-up inrush while tripping reliably on sustained overloads.

• Three-Pole Monitoring: Monitors all phases of a three-phase supply for balanced protection.

• Phase Loss & Unbalance Detection: Trips the circuit promptly during phase faults, reducing stress on the motor.

• Manual/Automatic Reset Options: Choose reset behaviour to suit your maintenance routine, with easy testing.

• Auxiliary Contacts (1NO + 1NC): Supports fault signalling to control panels or automation systems.

• Secure Screw-Clamp Terminals: Vibration-resistant wiring for reliable power and control connections.

• Compact Industrial Build: Easily mounts under compatible Schneider contactors or on DIN rail/panel for flexible use.

⚙️ Why Use the LRD03 Overload Relay?

Thermal overload relays like the Schneider LRD03 play an important role in protecting motors from damage caused by prolonged overcurrent or abnormal phase conditions. By reacting early to thermal stress, this relay helps you:

• Prevent motor overheating and winding failure before damage occurs

• Reduce unplanned downtime and maintenance in motor-driven systems

• Enhance safety with phase fault detection and auxiliary signalling

• Extend motor life through reliable, adjustable thermal protection

• Integrate seamlessly with Schneider contactor-based starters for efficient control panels

Whether you’re building new motor control installations or upgrading existing panels, the LRD03 is a practical choice for efficient, compact overload protection.

📌 Typical Applications

The Schneider Thermal Overload Relay LRD03 is ideal for:

• Motor starter assemblies in industrial control panels

• Small pumps, compressors & fan motors

• Conveyor and material handling drives

• HVAC motor protection and ventilation systems

• Automated machinery with small-capacity motors

This makes it a dependable choice for engineers, electricians, and maintenance professionals working with smaller three-phase motor systems.