Motor Overload Protection Thermal Relay

The vast majority of damages to electric motors are not caused by momentary disasters, but rather by the slow destruction of the insulation layer due to prolonged 'faulty operation' caused by sustained overheating. SPX high quality Motor Overload Protection Thermal Relay is the ultimate solution to this progressive threat. It is not a simple current switch, but a sophisticated thermal energy simulation and management system. The bimetallic components inside, like the "external simulated winding" of a motor, deform due to the heat generated when current flows through, accurately reproducing the real temperature rise inside the motor. When this' in vitro model 'determines overheating, it means that the motor body has also reached the safety critical point, and protection is immediately triggered. This is a direct and profound philosophy of protection based on the laws of physics.

The bimetallic strip connected in series in the main circuit of the motor generates corresponding heat with the magnitude of the current. The different thermal expansion coefficients of its two layers of metal cause the blade to bend to one side.
Bend and push the lever, and after a period of time inversely proportional to the severity of the overload, finally disconnect the normally closed control contact. For example, it may take tens of minutes to operate at 1.2 times the rated current, while it only takes a few seconds at 6 times the current. This inverse time characteristic perfectly matches the thermal endurance curve of the motor, which can withstand short-term large overloads but cannot tolerate long-term small overloads.
The customized Motor Overload Protection Thermal Relay protection feature originates from the physical properties of the material and can instinctively simulate the thermal behavior of the motor winding without any external programming or power supply. This reliability based on natural laws is rooted in materials science and is not affected by software vulnerabilities, electromagnetic interference, or grid fluctuations.

For long-term "sub-health" operation of 105% -150% rated current, electronic devices may be ignored due to threshold setting or signal filtering, but the heat of thermal relays will continue to accumulate until reliable operation, specifically preventing and treating this "chronic disease" that leads to insulation aging.
When a phase failure or severe imbalance occurs, the current of the healthy phase rises sharply. The internal differential mechanism of Motor Overload Protection Thermal Relay (such as "phase fault detector") can significantly accelerate the tripping process and provide efficient phase failure protection.
No need for auxiliary power supply, all metal and high-performance engineering plastic structure. In harsh industrial sites with dust, humidity, high temperature, and strong electromagnetic interference, it demonstrates the survival ability and stability that electronic devices cannot match.