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The thermal relay plays a pivotal role in determining the temperature control and operation of air conditioners. Mytour Supermarket will help you understand more about the structure, operating principle, and functions of the thermal relay in air conditioners through this article.
Thermal Relay in Air Conditioning: Structure, Operation Principle, and Functions
1. What is a Thermal Relay in an Air Conditioner?
Air Conditioning Thermal Relay: Structure, Operation, and Purpose
Thermal Relay in Air Conditioning
2. Operating Principle of Thermal Relay
The operating principle of the thermal relay relies on the expansion of heat-sensitive components inside, mainly bimetallic strips or thermal pellets, when heated. This is how the thermal relay ensures safety and protects the air conditioning system.
- Heat-Sensitive Component: Typically a bimetallic strip or thermal pellet, this component is made from two layers of materials with different thermal expansion coefficients. As the surrounding temperature increases, the different layers of material expand, leading to deformation or a change in the position of the heat-sensitive component
- Relay Activation: When the temperature reaches the specified limit, the heat-sensitive component will activate the mechanism inside the thermal relay. This mechanism typically includes mechanical parts such as electrodes and contacts
- Open or Close Electrical Circuit: When the mechanism inside the relay is activated, it can open or close the electrical circuit, depending on the specific design of the relay
- System Protection: If the thermal relay is used to protect devices such as compressors in air conditioning systems, refrigerators, freezers, or coolers, when the surrounding temperature exceeds the safe limit, the relay will cut off power to that device. This prevents the operation of the device in unsafe temperature conditions
Thermal relay operates based on the expansion of heat-sensitive components inside
3. Structure of Air Conditioner Thermal Relay
Air conditioner thermal relays have a relatively simple structure, helping to protect the air conditioning system from overload or malfunctions. Below is the basic structure of an air conditioner thermal relay:
- Lever
- Normally Closed Contact (NC)
- Normally Open Contact (NO)
- Adjustable Current Impact Screw
- Dual-Blade Strip
- Heating Wire
- Toggle
- Reset Button
Thermal relay in air conditioners has a relatively simple structure
4. Various Types of Modern Thermal Relays in Air Conditioners
Currently, there are numerous types of thermal relays in air conditioners, classified based on the following factors:
Based on Usage Needs:
- Single-Pole Thermal Relay
- Double-Pole Thermal Relay
Based on Structure:
- Open Type Thermal Relay
- Closed Type Thermal Relay
Based on Heating Method:
- Direct Heating Thermal Relay
- Indirect Heating Thermal Relay
- Mixed Heating Thermal Relay
These types of relays are chosen based on the specific needs of the application and the electronic protection requirements of the air conditioning equipment.
5. Role of Thermal Relays in Air Conditioning Systems
Thermal relays play a crucial role in safeguarding and optimizing the operation of air conditioners. Here are the key functions of thermal relays in air conditioning systems:
- Protection from electrical overload: Thermal relays are designed to interrupt the electrical circuit when the current exceeds a safe limit. This mechanism prevents the air conditioner from operating under overload conditions, protecting its components from damage
- Enhancing durability and stability: By preventing operation under overload conditions, thermal relays help the air conditioner operate more robustly and stably. Therefore, they increase the lifespan of the air conditioner and reduce the risk of malfunctions
- Minimizing damage issues: Thermal relays are often combined with fuses to provide comprehensive protection for the air conditioner. In case of incidents like overload or short circuits, the fuse will cut off the electrical circuit, and the thermal relay ensures that the air conditioner does not operate under unsafe conditions
Thermal relays for air conditioners enhance the durability and stability of the equipment
Note that thermal relays require a certain time to open and close the electrical circuit, so they are commonly used to protect against electrical overload rather than short circuits. For short circuit protection, other protective devices such as circuit breakers should be used.
Understanding the thermal relay of an air conditioner is crucial for both users and HVAC maintenance technicians. Hopefully, the information in this article has provided you with a clearer insight into the functions and roles of thermal relays in your home's air conditioning system.
