Schneider Electric LRD07L Overload Relay

Technical Overview

TeSys Deca differential thermal overload relay (1.6-2.5A, Class 20) with phase failure sensitivity, rated at 690V AC for reliable motor circuit protection.

Key Features

Thermal protection adjustment range from 1.6 to 2.5 A
Class 20 overload tripping curve ideal for longer motor starting times
Built-in phase failure and load unbalance detection mechanism
Integrates directly beneath compatible TeSys Deca LC1D09 to LC1D38 contactors
Equipped with 1 NO + 1 NC auxiliary contacts for fault signaling
Manual and automatic reset options with physical trip status indicator
Robust electrical screw clamp terminals conforming to multi-standard configurations

Technical Specification Matrix

Parameter	Value
Thermal Protection Range	1.6...2.5 A
Tripping Class	Class 20
Rated Operational Voltage (Ue)	690 V AC (0...400 Hz)
Rated Insulation Voltage (Ui)	690 V (Power circuit, IEC 60947-4-1) / 600 V (UL/CSA)
Rated Impulse Withstand Voltage (Uimp)	6 kV
Auxiliary Contact Composition	1 NO + 1 NC
Conventional Free Air Thermal Current (Ith)	5 A (Signalling circuit)
Phase Failure Sensitivity	Tripping current 130% of Ir on two phases, last one at 0
IP Rating	IP20
Operating Temperature	-20...60 °C (without derating)
Product Compatibility	LC1D09, LC1D12, LC1D18, LC1D25, LC1D32, LC1D38
Tightening Torque	1.7 N.m (Control and Power circuits)
Physical Weight (kg)	0.14
Dimensions L x W x H (cm)	7.6 x 4.5 x 6.6

Industrial Applications

1. High-Inertia Centrifugal Fan Protection

High-inertia industrial fans require extended start-up sequences where starting currents remain elevated. A standard Class 10 relay would nuisance trip. The Class 20 rating of the LRD07L allows the motor to draw start-up current for up to 20 seconds before initiating a thermal trip, while maintaining precise protection during standard continuous operation.

Problem Solved

Eliminates premature nuisance tripping during high-inertia motor start-up periods without sacrificing thermal overload safety.

High-InertiaClass 20 TrippingCentrifugal FanMotor Protection

2. Heavy-Duty Conveyor System Safeguard

Conveyors loaded with heavy materials present high starting torques and face operational risks of mechanical jams. Operating on a 3-phase system, a 0.75kW motor running at 400V requires close protective current matching in the 1.6-2.5A window. If a mechanical jam occurs or a supply phase fails, the LRD07L's integrated phase failure sensitivity detects the load unbalance and immediately disconnects power.

Problem Solved

Protects small conveyor motors from permanent damage caused by mechanical stall overcurrent or single-phasing events.

Conveyor SystemPhase Failure SensitivityOverload ProtectionBimetallic Relay

3. Industrial Fluid Mixing and Agitation

Mixers dealing with viscous fluids continuously endure load variations. This overload relay monitors the precise current draw of the mixer's motor within the 1.6-2.5A range. In the event of fluid thickening causing prolonged overload, the integrated 1 NO + 1 NC auxiliary contacts immediately trigger a localized signal alarm and safe-state PLC shutdown.

Problem Solved

Prevents catastrophic winding burnout in continuously loaded agitator motors through automated alarm auxiliary signaling.

Viscous MixingFault SignalingAuxiliary ContactsPLC Shutdown