An overview of the recovery time and start time of the self recovery fuse action is as follows
Self recovery fuse action recovery time:
Since the action principle fuses a dynamic balance of energy, through the self recovery fuse current due to the relationship between the fuse to generate heat, the heat generated in whole or in part is dissipated to the environment, without dissipating heat will improve the temperature.
Normal working temperature is low, the heat and the heat emitted to the balance. Since the recovery of the fuse is in a state of low resistance, no action, when the current through the fuse to increase or increase the ambient temperature, but if the heat generated by the heat balance, the self recovery fuse is still not action. When the current or the ambient temperature increases when the self recovery fuse will reach a higher temperature, if the current environmental temperature or continue to increase, the heat generated will be greater than the heat dissipated, the self recovery fuse temperature surge, at this stage, very small temperature changes will cause a substantial increase in resistance, then the self recovery fuse in a high impedance state protection, impedance increase limit current, current drops sharply in a very short period of time, so as to protect the circuit equipment from being damaged, as long as the voltage applied to the heat generated by the self recovery fuse emits enough heat, in the condition of components can be always in motion state (Gao Zu). When the applied voltage is lost, the self recovery fuse can be automatically recovered.
Self recovery fuse start protection time:
When we choose to restore the fuse, we want to know when the circuit fault current, since the recovery of the speed of the protection of the fuse is timely enough to play the role of protective circuit equipment.
Here to tell you that there are many models of self recovery fuse, the different models of the start of the speed of protection is not the same. And the same type of fault current in the different fault of the time required to start the protection is not the same.
We discuss the starting time of self recovery fuse, can only give a general range, unless specified in a specific model, in order to give a relative value at the time of the corresponding. The time for a plug-in type of self recovery fuse protection action reaction is longer than that of the fuse.
If you must give a self recovery fuse to start the protection of the time range of it? The need to have a premise, is the size of two times the current definition of current work for fault current minimum start protection, at two times the normal current value, all plug-in self recovery fuse start protection time range approximately between 0.1s~100s, why is there such a large range, different models required to start different time.
The duration of protection is regular, one is the size of the same components have a relationship with inverse relationship; the other is the size of the fault current is inversely proportional to the relationship between the.
With the size of the components is inversely proportional to that in the same series, such as 250V series plug-in fuse, the less current models of the components made smaller, 2 times the normal current, because of its small size and fast heat, start protection time is fast. The bigger the film, the longer the time required to start the protection, the higher the voltage requirement, the larger the film is.
The size of the fault current is inversely proportional to the relationship, this is a good understanding, that is, the greater the fault current of the device, the faster the heat, the faster the protection. For example, in the fault current is 3, 4 times the normal operating current, many models of protection time can be started within 1 second to protect.
In the actual application, the fault current we can follow specific selection and actual value to confirm, general can refer to self recovery fuse device "25 C typical action time curve obtained near the time value. This gives a 250V series plug-in fuse 25 C typical action time curve".