Siemens 3TH8031-0AG2 Three-Phase Contactor Relay

Siemens 3TH8031-0AG2 is a three-phase contactor relay designed to switch three-phase loads in electrical control panels. It provides three normally open main contacts and one normally closed auxiliary contact, enabling both motor control and simple feedback or interlock wiring within a single device. The coil is rated at 110 VAC (50/60 Hz), suited for standard automation control circuits common in industrial environments. As part of Siemens’ 3TH-series contactors, this model offers a compact, robust solution for starting and stopping three-phase motors and other high-power loads, with straightforward wiring of the auxiliary NC contact to PLC inputs or interlock circuits. The 3NO main contacts handle the three-phase switching while the auxiliary contact supports monitoring or safety-related logic in control schemes. When selecting this model, ensure the main contact rating matches your load and that the 110 VAC coil voltage aligns with your control cabinet voltage. The 3TH8031-0AG2 designation identifies a specific combination of main contact arrangement and auxiliary contact configuration within Siemens’ lineup, providing compatibility with Siemens control systems and standard industrial wiring practices for motor control panels.