The Schneider Electric LRD22TQ is a differential thermal overload relay from the TeSys Deca line, designed for motor protection in three-phase circuits. Its thermal protection adjustment range covers 16 to 24 A, with a Class 10A tripping characteristic per IEC 60947-4-1 — 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. The 1 NO + 1 NC auxiliary contact set provides a separate signal circuit for the PLC or annunciator, rated 1.5 A at 240 V AC-15 for signalling duty.
The 16-24 A adjustment range sets the relay for motors with a full-load current in that band — common for 7.5 to 10 HP motors at 460 V, or 5 to 7.5 HP at 230 V. The Class 10A trip class is the standard for general-purpose induction motors; if your application has a long acceleration time or high-inertia load, you may need a Class 20 or 30 relay instead. Phase-failure sensitivity is built in: the relay trips at 130% of the set current on two phases when the third is at zero — this protects the motor from single-phasing, which is the most common cause of winding failure in field applications. Rated insulation voltage is 690 V AC per IEC 60947-4-1, and 600 V per UL/CSA — sufficient for 480 V and 600 V class systems. Impulse withstand is 6 kV, so it coordinates with standard motor-starter components in a panel.
Listed to 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, and GB/T 14048.4/14048.5. Also carries EN 50495 for safety-related applications. Flame retardance is V1 per UL 94.