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Auto Fuse for Refrigerator B15135.4-5 Thermo Fuse Home Appliance Parts

Short Description:

Introduction: Thermal Fuse

A thermal fuse is a new type of electrical overheating protection element. This kind of element is usually installed in heat-prone electrical appliances. Once the electrical appliance fails and generates heat, when the temperature exceeds the abnormal temperature, the thermal fuse will automatically fuse to cut off the power supply to prevent the electrical appliance from causing a fire.

Function: cutoff the circuit by detecting overheat.

MOQ: 1000pcs

Supply Capacity: 300,000pcs /month

Product Detail

Product Tags

Product Parameter

Product Name Auto Fuse for Refrigerator B15135.4-5 Thermo Fuse Home Appliance Parts
Use Temperature control/Overheat protection
Electrical Rating 15A / 125VAC, 7.5A / 250VAC
Fuse Temp 72 or 77 Deg C
Operating Temperature -20°C~150°C
Tolerance +/-5°C for open action(Optional +/-3 C or less)
Tolerance +/-5°C for open action(Optional +/-3 C or less)
Protection class IP00
Dielectric Strength AC 1500V for 1 minute or AC 1800V for 1 second
Insulation Resistance More than 100MΩ at DC 500V by Mega Ohm tester
Resistance Between Terminals Less than 100mW
Approvals UL/ TUV/ VDE/ CQC
Terminal type Customized
Cover/Bracket Customized


- Automotive seat heaters
- Water heaters
- Electric heaters
- Anti freeze sensors
- Blanket heaters
- Medical applications
- Electrical appliance
- Ice makers
- Defrost heaters
- Refrigerated
- Display cases



The thermal fuse is the same as the fuse we are familiar with. It usually only serves as a powerful path in the circuit. If it does not exceed its rated value during use, it will not fuse and will not have any effect on the circuit. It will fuse and cut off the power circuit only when the electrical appliance fails to produce abnormal temperatures. This is different from a fused fuse, which is blown by the heat generated when the current exceeds the rated current in the circuit.


What are the types of Thermal Fuse?

There are many ways to form a thermal fuse. The following are three common ones:
• The first type: Organic Thermal Fuse


It is composed of a movable contact (sliding contact), a spring (spring), and a fusible body (electrically nonconductive thermal pellet). Before the thermal fuse is activated, the current flows from the left lead to the sliding contact and flows through the metal shell to the right lead. When the external temperature reaches a predetermined temperature, the organic melt melts and the compression spring becomes loose. That is, the spring expands, and the sliding contact is separated from the left lead. The circuit is opened, and the current between the sliding contact and the left lead is cut off.

• The second type: Porcelain Tube Type Thermal Fuse


It is composed of an axisymmetric lead, a fusible alloy that can be melted at a specified temperature, a special compound to prevent its melting and oxidation, and a ceramic insulator. When the ambient temperature rises, the specific resin mixture begins to liquefy. When it reaches the melting point, with the help of the resin mixture (increasing the surface tension of the melted alloy), the molten alloy quickly shrinks into a shape centered on the leads at both ends under the action of the surface tension. Ball shape, thereby permanently cutting off the circuit.

• The third type: Square Shell-type Thermal Fuse
A piece of fusible alloy wire is connected between the two pins of the thermal fuse. The fusible alloy wire is covered with a special resin. Current can flow from one pin to the other. When the temperature around the thermal fuse rises to its operating temperature, The fusible alloy melts and shrinks into a spherical shape and attaches to the ends of the two pins under the action of surface tension and the help of special resin. In this way, the circuit is permanently cut off.


- The industry standard for over-temperature Protection
- Compact, but capable of high currents
- Available in a wide range of temperatures to offer
design flexibility in your Application
- Production according to customers’ drawings


How does a Thermal Fuse work?

When the current flows through the conductor, the conductor will generate heat because of the resistance of the conductor. And the calorific value follows this formula: Q=0.24I2RT; where Q is the calorific value, 0.24 is a constant, I is the current flowing through the conductor, R is the resistance of the conductor, and T is the time for the current to flow through the conductor.

According to this formula, it is not difficult to see the simple working principle of the fuse. When the material and shape of the fuse are determined, its resistance R is relatively determined (if the temperature coefficient of resistance is not considered). When current flows through it, it will generate heat, and its calorific value will increase with the increase of time.

The current and resistance determine the speed of heat generation. The structure of the fuse and its installation status determines the speed of heat dissipation. If the rate of heat generation is less than the rate of heat dissipation, the fuse will not blow. If the rate of heat generation is equal to the rate of heat dissipation, it will not fuse for a long time. If the rate of heat generation is greater than the rate of heat dissipation, then more and more heat will be generated.

And because it has a certain specific heat and quality, the increase in heat is manifested in the increase in temperature. When the temperature rises above the melting point of the fuse, the fuse blows. This is how the fuse works. We should know from this principle that you must carefully study the physical properties of the materials you choose when designing and manufacturing fuses, and ensure that they have consistent geometric dimensions. Because these factors play a crucial role in the normal operation of the fuse. Similarly, when you use it, you must install it correctly.


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