Frequently Asked Questions (FAQs)
What is the difference between a self recovery fuse and a circuit breaker
Both circuit breakers and self recovery fuses ensure circuit safety. A circuit breaker is an electromechanical device designed to "trip" or open contacts when the current exceeds the rated value, preventing the flow of current and preventing damage to electrical equipment or circuits. After the circuit breaker trips, it can be reset through the switch. Circuit breakers are an important component of any distribution system. The self restoring fuse (PPTC) performs a similar function, and if the current exceeds the rated value, it will "trip". The difference is that when there is no longer an overcurrent situation, the self recovery fuse will automatically reset. When the circuit breaker trips, the current is completely cut off, and the self recovery fuse can still allow small currents to pass through.
What are the different types of resettable fuse fuses?
There are two types of self-healing fuses: polymer PTC and ceramic PTC. Self restoring fuses can also be distinguished by their external dimensions.
Do you need to lower the rating of the resettable fuse fuse?
Lowering the rated value of the self recovery fuse means selecting devices with a rated current higher than the application requirements. Temperature can affect the reliable operation of self recovery fuses and may require a derating. For more information on derating, please refer to the specifications of the fuse manufacturer.
Will self restoring fuses wear out?
Repeated tripping and resetting cycles may cause the PPTC fuse to withstand thermal stress, thereby degrading its polymer matrix. Regular inspection and replacement of PPTC fuses that have undergone multiple trip reset cycles are also important.
What is the function of a self restoring fuse?
Self restoring fuses can protect electronic circuits from overvoltage or overcurrent events. It is a passive safety device. When the current flowing through the fuse exceeds the rated value, heat is generated, causing the device to expand. This will increase its resistance and reduce the current flowing through the fuse.
What are the drawbacks of self restoring fuses?
Compared to traditional fuses, PPTC fuses have higher resistance.
Compared to traditional fuses, PPTC fuses have a slower response time, which can delay circuit protection and potentially cause damage.
PPTC fuses have limitations in maximum voltage and operating temperature, limiting their use in certain applications.
The repeated cycling of PPTC fuses may lead to performance degradation over time, thereby reducing their reliability and service life.
Is the self recovery fuse safe?
If used correctly and within the rated specification range, a self restoring fuse is safe.
Does the self restoring fuse have polarity?
The self restoring fuse has no polarity.
How do I know if my self recovery fuse is broken?
Multiple methods can be used to identify failed self-healing fuses, including resistance and current measurements, visual inspection, and circuit faults. This method depends on the fuse and circuit used.
What is the working range of a self restoring fuse?
The working temperature range of self recovery fuses is generally between -40 ℃ and+85 ℃.
What is the difference between PPTC and fuses?
Fuses and PPTC are both overcurrent protection devices. Fuses completely prevent the flow of current during overcurrent events, while PPTC reduces the current to a safe level. In addition, the fuse must be replaced after the trip; PPTC will automatically reset.
What is the rated value of the PPTC fuse?
The specifications of PPTC fuses include multiple ratings, including holding current, tripping current, voltage, and power. The rated value of PPTC fuse is crucial to ensure that it provides the appropriate level of protection for the circuit it is connected to. It is important to carefully consider the electrical requirements of the circuit and select PPTC devices with appropriate ratings for specific applications.
How does the PPTC fuse work?
At normal temperatures, conductive particles in polymer PTC will form many conductive paths.
Under normal working conditions, PPTC has low resistance and allows for current flow. When a large current passes through a fuse, the temperature will rise above the switching temperature of the device. As a result, the polymer undergoes a phase transition from crystalline to amorphous, leading to a non-linear increase in device resistance. This will disconnect the circuit path and provide circuit protection.
What does PTC in a fuse represent?
PTC represents the positive temperature coefficient.
