The LR3D3323 is a non-differential thermal overload relay from the TeSys Deca series, designed for motor protection in industrial control panels. It provides adjustable thermal protection from 23 to 32 A with a Class 10A tripping curve, meaning it will trip within 10 seconds at 7.2× the set current — fast enough to protect standard induction motors during a stall or locked-rotor condition without nuisance tripping on normal starts. The EverLink BTR screw terminals on the power circuit accept 1 to 35 mm² conductors, while the control circuit uses spring terminals for 1 to 2.5 mm² — a mixed-termination design that suits both panel-builder preference and field retrofit.
The 23-32 A adjustment range covers a common motor current band for 7.5 to 15 kW motors at 400 V three-phase. The Class 10A overload class is the standard for general-purpose motor starting — it allows enough inrush time for a direct-on-line start but clears quickly on a jam. Phase-failure sensitivity is built in: the relay trips at 130 % of the set current (Ir) on two phases when the third drops to zero. This protects motors against single-phasing, which can overheat windings in seconds under load. Temperature compensation is active from -20 to 60 °C, so the trip curve stays accurate across the panel's ambient range without manual derating.
The LR3D3323 carries approvals across the major industrial regions: EN/IEC 60947-4-1 and 60947-5-1, UL 60947-4-1 and 60947-5-1, CSA C22.2 No 60947-4-1 and 60947-5-1, plus GB/T 14048.4 and GB/T 14048.5 for the Chinese market. Rated insulation voltage (Ui) is 600 V for UL/CSA and 690 V for IEC, so it fits 480 V and 600 V North American panels as well as 690 V European installations. Flame retardance is V1 per UL 94. Dielectric strength tested at 1.89 kV at 50 Hz per IEC 60947-1. The signalling circuit is rated for 5 A conventional free air thermal current (Ith), with fuse protection specified at 4 A gG or BS.