How to make our electrical circuit safe? Due to short circuit if there is a large amount of current flow and thus will damage the circuit severely by enhancing the heat. Installations will be burned by the heat and generate more power looms and will lead to an electrical fire accident. This has become a major issue and most of the technicians will offer their best to avoid the situation from happening on aircraft or any other device. Here are few devices for safeguarding the electric circuits: 1) Fuses 2) Circuit Breakers 3) Current Limiters Apart from the above-mentioned device, there are other devices for safeguarding the situations like a reverse current, over/under- frequency, over/under-voltage, phase unbalance, etc., but it is not something which is focused over here. 1) Fuses For the purpose of short circuit protection, a base element called fuse is used. It is a device with thermal energy concept and low melting point involved in ceramic case or glass. There is a low current carrying capacity in a fusible element for safety purpose. The circuits are melted and interrupted in the case of short circuit. Here is a few list of elements used for fuses like lead, tin, bismuth, silver and other alloys of materials. For instance in aircraft landing which has emergency circuit, there is no requirement for implement fuses advanced rating for cable protection. It is very much mandatory in the development for installing the fuses near to power source due to fulllength wire protection. 2) Current limiters To some defined value there is definitely some limit of current in the current limiters. You can find two types of limiters over here like the one similar to heavy-duty fuses: to current characteristic, they have different time but otherwise, they are thermal devices. Limiting resistor is an alternative option because it is used for protecting DC circuits which have high initial starting current for instance starter engine. With starter generators especially during highest current occurrence, these limiters are mostly used. For reducing the current in the initial starting of the motor limiter resistor is implemented. After the initialization process is terminated and it has a constant speed in motors the power supply circuit is switched off. 3) Circuit Breakers From fuses and current limiters there is a difference when compared to Circuit breakers as during failure they interrupt and isolate the circuit. By heating the bi-metallic element the working principle is actuated with the current passing through the switching unit. It can also be considered as fuse with switch capability. There is no hard and fast rule in using it and it is quite simple and saves a lot of maintenance. During failure it is possible to resolve the fault and give a verification
by circuit breaker as all the contacts to the switch unit will be stopped if the fault current exists in the circuit. Based on three elements you can find the construction for example contact switch and mechanical latching mechanism, bi-metal thermal element and mechanical latching mechanism along with push button. Join the courses in electrical engineering to make your career in this field successfully.