Siemens 3RU2126-1GB0 Thermal Overload Relay 3RU2126-1GB0

Siemens 3RU2126-1GB0 is a SIRIUS thermal overload relay designed for motor protection when used with Siemens 3RU2 contactors. It provides inverse-time overload protection for three-phase motors rated 4.5–6.3 A on a Size S0 frame with Class 10 accuracy, and it mounts directly to a compatible 3RU2 contactor using screw terminals for both the main current path and the auxiliary circuit. The relay includes one normally open and one normally closed auxiliary contact (1NO + 1NC) to support interlocking or feedback signals in the control circuit, and it offers both manual and automatic reset after a trip. This model is a standard component in Siemens Sirius motor-protection schemes, offering compact protection in an S0 package suitable for integration in control cabinets and machine enclosures, helping to prevent motor damage from overloads or phase failure while enabling straightforward maintenance and reset procedures.