Siemens Overload relay for motor protection, size S0, 5.5 - 8AProduct Overview The Siemens 3RU2126 1HB0 is a SIRIUS thermal overload relay designed to protect three phase motors against overload and phase failure. Part of the 3RU21 series, this relay features an adjustable current setting range of 5. 5 A to 8 A and a Class 10 tripping characteristic, ensuring reliable protection under standard motor starting conditions. It is intended for direct mounting onto compatible SIRIUS contactors, forming a compact and