Thermal overload relay TeSys LRD 12-18A class 10 screw terminals LRD21

Overload Relays TeSys LRD – Reliable Motor Protection

TeSys LRD 21 overload relay is a robust and versatile device designed to protect electric motors. It belongs to the TeSys Deca series and provides effective protection against overload and phase failure, which is crucial in demanding industrial conditions. Thanks to the adjustable current range, from 12 to 18 A, it allows for precise adjustment to the specifics of the protected circuit. Compatibility with LC1D18, LC1D25, LC1D32 and LC1D38 contactors simplifies integration into existing control systems.

The LRD21 relay has built-in mirrored auxiliary contacts (one normally open and one normally closed), which expands its functionality and allows it to be used in more complex applications. Mounting is possible directly under the contactor or on a mounting plate/rail, providing installation flexibility. The device is characterized by high resistance to environmental conditions and mechanical strength, guaranteeing long-lasting and reliable operation.

Characteristics and application

The LRD21 thermal relay is designed to protect AC circuits and motors against various types of overloads – from short-term current surges during start-up to long-term loads leading to winding overheating. Class 10A tripping ensures a quick response to overloads, minimizing the risk of motor damage. In addition, the phase failure detection function protects against serious failures caused by voltage asymmetry.

Application:

• Motor protection in industrial applications
• HVAC systems (heating, ventilation, air conditioning)
• Energy management – reducing motor failures translates into energy savings
• Applications requiring frequent switching (switching frequency up to 1 time per second)

Construction and functionality

The LRD21 relay is equipped with a red STOP button for manual shutdown and a blue RESET button to restore operation after tripping. Automatic reset allows the device to be restarted after the cause of the trip has subsided (depending on the settings). Screw terminals provide a safe and durable connection for wires with a cross-section from 1 to 6 mm² (depending on the type of connector). A wide range of operating temperatures (-20°C to +60°C) allows it to be used in various environmental conditions. The device meets a number of safety standards (IEC 60947-4-1, EN 60947-4-1), which confirms its high quality and reliability. The rated operating voltage is 690V AC.