The Schneider Electric TeSys LRD15306 is a differential thermal overload relay from the TeSys Deca series, designed for motor protection in three-phase circuits. It provides Class 20 overload protection with a thermal protection adjustment range of 23 to 28 A, meaning it can handle motor full-load currents within that band and trip within the Class 20 curve (typically 20 seconds at 7.2× Ir). The relay is rated for operation on AC networks up to 690 V at 0–400 Hz, with an impulse withstand voltage of 6 kV. It complies with EN/IEC 60947-4-1 and -5-1, plus UL and CSA equivalents, so it fits into panels built to either IEC or North American code. Phase failure sensitivity is built in: it trips at 130 % of Ir on two phases when the third is at zero, which protects motors against single-phasing.
Because it is obsolete, there is no official manufacturer successor listed for this specific code. If a direct replacement is needed, a parametric cross-reference within the TeSys family may be possible, but that depends on the mounting, current range, and auxiliary contact configuration required. A sourcing specialist can confirm fit against the original application.
The 23–28 A adjustment range is the key selection parameter: it must match the motor's full-load current (FLC). Class 20 tripping means the relay allows a moderate overload before tripping — suitable for standard induction motors that can handle a brief 20-second start or stall without damage. The ambient operating range of -20 to 60 °C without derating covers most indoor panel environments, but if the panel runs hotter than 60 °C, the relay must be derated or relocated. The auxiliary contact composition is 1 NO + 1 NC, which is standard for signalling the tripped state back to a PLC or contactor coil circuit. The signalling circuit is rated for 1.5 A at 240 V AC-15 and 0.1 A at 250 V DC-13 — enough for a typical PLC input or relay coil, but not for direct motor switching. Mounting options include plate or rail with specific accessories, or directly under the contactor.