Siemens Thermal Overload Relay 12V DC

The Siemens Thermal Overload Relay for 12V DC is a device designed primarily for the protection of motors and electrical loads from overheating caused by overload or phase failure. It operates on a current-dependent principle where the relay uses bimetal strips that heat up as the current rises above a set rated motor current, eventually triggering auxiliary contacts that switch off the load via an associated contactor. This action prevents damage from excessive motor heating.

Key features and functionalities include:

• Current-dependent overload protection based on the motor's rated current, adjustable via a rotary knob.

• Protection against phase failure which minimizes heating from single-phase operation during a phase loss.

• The relay has inverse-time delayed tripping characteristics to optimize load protection.

• It can be manually or automatically reset after tripping.

• The relay often comes with visual indicators for the tripped state and test functions to ensure correct operation.

• It is suitable for both AC and DC motors, including single-phase DC loads.