LRD340 Electric Thermal Overload Relay – 1NO + 1NC, 30 – 40. From Schneider Electronic this is the LRD 340 TeSys Differential thermal overload relay designed to protect ac circuits against overloads, phase failure, long starting time and prolonged motor stalling. LRD Thermal overload relays are reliable and cover motor ratings up to 150 A plus they can be used with TeSys D contactors providing you with a compact starter.