Customized Motor Thermal Protector (Thermostatic Switch)

The motor thermal protector is a protective device that automatically cuts off the circuit through temperature or current changes. The core function is to prevent the motor from being damaged by overheating, overload or stalling. The following are the key points:

Car wiper motor overload and overheat protector 6AP

17AM Motor Thermal Protector Normally Closed NC Thermostat Sensor KLIXON 17AM022

Thermal Overload Protector Options for small Electric Motors & Gearmotors

⚙️ 1. Core working principle
‌Bimetallic strip structure‌: It is composed of two metal strips with different thermal expansion coefficients. Quando la temperatura aumenta, the metal strips bend and deform due to the expansion difference, triggering the mechanical linkage to cut off the circuit; it automatically resets and resumes conduction after the temperature drops.
‌Current-temperature dual response‌: Some models (such as three-phase thermal protectors) monitor current overload and winding temperature at the same time. When overloaded, the circuit is quickly cut off within 4-10 seconds to avoid stall damage.

Come funziona:
Overheating Detection:
Thermally protected motors typically use temperature sensors, such as PTC thermistors or KTY sensors, which are embedded within the motor windings. These sensors monitor the temperature of the motor and send signals to a thermal protection device.

Power Cutoff:
When the motor’s temperature rises beyond the safe limit, the thermal protection device, which can be a bimetallic switch or a similar mechanism, disconnects the power supply, shutting down the motor.

Automatic Restart:
After the motor cools down, the thermal protection device typically resets, allowing the motor to be restarted manually or automatically.

Benefits:
Prevents Damage:
Thermal protection helps prevent overheating, which can lead to damage to the motor’s insulation, windings, and other components.
Extends Lifespan:
Prevenendo il surriscaldamento, thermal protection contributes to a longer lifespan for the motor.
Sicurezza:
It minimizes the risk of fire or other hazards caused by motor overheating.

🔍 2. Main types and technological evolution

Nota: Tianyin Electromechanical’s patented technology significantly improves response reliability by optimizing the combined structure of bimetallic strips (such as adding overcurrent protection components).

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5AP/2MP 50℃-180℃ overcurrent, overheating motor thermal protector

📌 3. Key selection parameters

⚠️ 4. Precautions for use
‌Installation specifications‌:
The lead bending must be more than 6mm away from the root to avoid damage and poor contact;
After high-temperature welding, it must be cooled for more than 30 seconds to prevent the protector from being damaged by heat.
‌Environmental adaptability‌:
Avoid using non-sealed protectors (such as traditional contactors) in highly polluted environments;
Regularly check the fatigue and aging of bimetallic strips and replace them in combination with the equipment maintenance cycle.
‌Function conflict avoidance‌:
Automotive motors with anti-pinch function need to adopt software temperature control solutions to avoid hardware protectors interfering with obstacle detection.

♻️ 5. Troubleshooting
Common reasons why the motor burns but the protector does not operate:
‌Wiring error‌: The protector is not connected in series in the main circuit of the motor;
‌Set value is too high‌: The action temperature or current threshold setting exceeds the motor tolerance range;
‌Response delay‌: The bimetal strip requires heat accumulation time and cannot cope with instantaneous short-circuit faults.
It is recommended to give priority to products that have passed the short-circuit test (Clause 18.101) specified in the GB/T 14536.3-2022 standard to ensure reliability under extreme working conditions.