﻿ Current fuse & Resettable fuse & Thermal Fuse difference between_

China Thermal Protector Manufacturer

Current fuse & Resettable fuse & Thermal Fuse difference between

Protection principle distinguish three fuses:
1. Current Insurance and self-recovery fuse, which protects the current in the circuit, it is also known as overcurrent protection devices,
Difference between the two:Traditional fuse overcurrent protection, protection only once, blown in need of replacement,And since the resumption of fuses with the flow overheating protection, automatic recovery dual function.
2. The thermal fuse is in product design, overheating protection element heating element, also referred to as thermal fuseal fuse

my company am now on the specific features and parameters for the three points off the fuse will be:

First, the specific parameters of current fuse.
1, current protection fuse wire Material:
The fuse wire resistance rate is relatively large and relatively low melting point of silver-copper alloy called current fuse,Common household fuse previous lead-antimony alloy,Later, because the resistance is high enough,Low enough melting point, Replaced by a silver-copper alloy, You can achieve the purpose of the protection circuit. .

2, the role of over-current protection fuse is:
When a circuit failure or abnormal,With the current rising,And increased current circuit may damage some important devices or expensive devices,There may even cause a fire burned circuit. fuse will be in the current abnormally elevated to a certain height and heat of the moment, Self-fusing current is cut off, And thus play a role in protecting the safe operation of the circuit, To avoid a variety of security risks.

3, the current fuse working principle:
Because the silver-copper alloy of low melting point, resistance is large, When current flows through the silver-copper alloy, Because there is a certain resistance conductor, So it will heat conductor. And heat followed the formula: Q = 0.24I2RT; where the calorific power Q, is a constant 0.24, the I is the current flowing through the conductor, R is the resistance of the conductor, T is the time current flows through the conductor; So we can see that the formula of simple fuse works, and When the temperature rises, the melting point of silver-copper alloy, Silver-copper alloy fuse itself will cut off the current.

Current fuse image

Two: since the resumption of fuse protection specific parameters:
1, since the resumption of insurance protection of the fibroin material:
Resettable fuse is an overcurrent protection of electronic components, With the flow overheating protection, Double protection with automatic recovery, Organic macromolecule polymer at a high pressure, high temperature vulcanization reaction conditions, Mix material after adding conductive particles, Through a special process from processing.

2, since the resumption of fuses to protect the principle of selection:

Because the self-recovery overcurrent protection fuses have thermal protection, When where product modeling, it must take into account the current, Voltage and ambient temperature on the product works properly.
Selection To determine the following parameters of the circuit:
a maximum operating ambient temperature b c standard operating current Maximum operating voltage (Umax) d maximum fault current (Imax)
Choose from recovery circuit can adapt to the ambient temperature and the maximum standard operating current of the fuse element
{Ambient temperature reduction temperature (℃) operating current (A)} table and selects a maximum ambient temperature of the circuit that most closely matches temperature.

3, resettable fuse action principle:
When the line short circuit or overload, Flows through the heat recovery from high-current fuse the polymer produced by polymerization of the resin melt, Bulk increased rapidly, forming a high-impedance state (B), Current operating current will decrease rapidly, Thus limiting and protection circuits. When troubleshooting, Circuit current is back to normal after, Resettable fuse again cooling and crystallization, Volume shrinkage, the conductive particles form a conductive path, Polymer reverts to a low resistance state, Product return to normal working condition.
And completion of the entire work over the circuit protection, without artificial replacement. As long as the heat generated by the applied current is higher than the PPTC element gives off heat, Polymer will change in the state have always been in the operating state (high impedance). When current is applied disappear, Resettable fuse can be automatically returned to power.

Three: temperature fuse specifications:
1, the temperature fuse the basic material:
Temperature fuse into organics temperature type temperature fuse, temperature fuse type alloy wire.

2. The temperature fuse working principle:
Also called thermal fuse thermal fuse (GB GB9816.1-2013),Temperature sensing fuse can overheat protection of electrical and electronic products produced in a non-normal operation, Thereby cutting off the circuit to prevent the occurrence of fire, the temperature fuse after fuse can not be used again, Fusing temperature only in action once, Temperature fuse is divided into low-melting alloy and the temperature-sensitive shape memory alloys as well as trigger-shaped form, etc.  (Thermal fuse to prevent electrical heating appliances or heat it to high temperature protection.

Although the temperature fuse is designed to have high reliability, But a single temperature fuse can cope with unusual circumstances, after all, it is limited. It also has some disadvantages,
First, it can not be restored, as good as PTC, PTC even if accidental failure resulting action, Once the troubleshooting, the product can continue to work. Once the temperature fuse action, The entire product can no longer work.

Thermal fuse image
to sum up:
Three kinds of fuses are specifically works with different uses, In a variety of circuit protection design has its own strengths and weaknesses. Dongguan Yaxun long-term commitment of various electronic components electronic product development and research protection. Welcome customers to inquire, I will give you a reasonable product recommendations.

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