Siemens 3RU21261KB0 9.0-12.5 Thermal Overload Relay

Siemens 3RU21261KB0 9.0-12.5 Thermal Overload Relay 

The Siemens 3RU21261KB0 is a thermal overload relay used to protect electric motors from damage caused by overloads or phase failure. It's designed to automatically disconnect the motor when unsafe conditions are detected.

Key Features:

Adjustable current range: 9 to 12.5 amps

Trip class: Class 10 (trips in about 10 seconds during overload)

Mounting: Fits directly onto Siemens SIRIUS 3RT contactors (Size S0)

Reset options: Manual or automatic reset, with test and stop functions

Connection type: Screw terminals for wiring

Protection rating: IP20 (finger-safe front)

Compact size: Saves space in control panels

How It Works:

When the motor draws too much current or loses a phase, the relay heats up internally and triggers a switch to shut off power. This prevents damage to the motor. It can be reset manually or automatically and has a visual trip indicator.