Thermal protector overload protection of high-power electric tools

　　Thermal protector overload protection of high-power electric tools

In recent years, with the continuous development of science and technology, the application range of high-power power tools has become more and more extensive, such as drilling machines, electric hammers, grinders, etc. However, there is a risk of overloading these power tools due to long periods of high load operation. In order to protect the performance and safety of power tools, thermal protectors are widely used in power tools as a common overload protection device. This article will specifically introduce the principle, structure and use of thermal protectors in overload protection of high-power electric tools.

1. Principle of thermal protector

The thermal protector is a temperature-sensitive electronic component. Its main principle is to use the change in resistance of the thermistor at a specific temperature to control the switching circuit. When the power tool generates excessive temperature during operation, the thermal protector will sense the temperature change and cut off the current supply by controlling the switch circuit to protect the power tool from overload.

2. The structure of the thermal protector

Thermal protector generally consists of thermistor body, leads, terminals and protective shell. The thermistor is the core component of the thermal protector. It can choose different materials according to different operating temperature requirements. Common thermistor materials include tin zinc oxide, manganese copper, etc. The leads connect the thermistor body and terminals for transmitting current and signals. The protective shell plays the role of protecting the thermal protector from the influence of the external environment.

3. How to use thermal protector

1. Installation: The thermal protector is usually installed in the power supply system of the power tool and can be directly plugged into the power socket or connected to the circuit inside the power tool.

2. Parameter setting: According to the rated power and operating requirements of the power tool, the parameters of the thermal protector need to be set. This is generally achieved by selecting the appropriate thermistor material and adjusting the operating temperature of the thermal protector.

3. Working principle: When the temperature of the electric tool exceeds the operating temperature set by the thermal protector during operation, the resistance of the thermistor changes, and the thermal protector will immediately cut off the current supply to protect the electric tool from overload. damage. When the temperature returns to a safe range, the thermal protector will automatically return to normal working condition.

4. Advantages of thermal protector

1. High sensitivity: The thermal protector responds quickly to temperature changes and can cut off the current supply in time to prevent the power tool from being damaged by high temperature heat.

2. Stable and reliable: The thermal protector uses a thermistor with high stability and reliable electronic components, which can work stably for a long time and has a long service life.

3. Easy to maintain: The thermal protector is installed in the power tool’s power system. When a fault occurs or needs to be replaced, it can be easily maintained or replaced.

5. Application examples of thermal protectors in high-power electric tools

Taking a drilling machine as an example, this electric tool is prone to excessively high temperatures when running at high speed, generating heat for the motor and other key components, posing a risk of damage. In order to protect the performance and safety of the drilling machine, a thermal protector is installed in the power supply system of the drilling machine. When the temperature of the drilling machine exceeds the operating temperature set by the thermal protector during operation, the thermal protector will immediately cut off the current supply to avoid further damage to the drilling machine by heat.

6. Conclusion

As a common and effective overload protection device, the thermal protector plays an important role in high-power power tools. It protects power tools from overload damage by sensing temperature changes and cutting off the current supply. Thermal protectors have the advantages of high sensitivity, stability, reliability, and easy maintenance, so they are widely used in high-power power tools. With the continuous development of technology, the performance and functions of thermal protectors will continue to improve, providing a more reliable guarantee for the safe use of power tools.