Most electrical circuits and electronic equipment come with inbuilt circuit protection in the form of fuses or circuit breakers. This is important because it can protect the components of the circuit and the equipment being used in case of circuit overloads. It is also a safety measure to protect the person operating the equipment.
A fuse will protect the device when there is a risk of excessive current flowing through the circuit.
More about Fuses.
What is a fuse? A fuse is a small device with two metal caps and a metal wire strip in between. It is housed in a glass or ceramic casing. It is connected in the circuit in such a way that it can be quickly replaced after an event of overcurrent blows it.
How does a fuse work? A fuse is built such that it cannot withstand high currents. It is placed in a circuit so that in case of high currents, it will help to break the circuit and protect other components from getting damaged due to an overcurrent. The metal wire strip between the two terminals of the fuse will break, thus causing the current to stop. The high currents heat the metal wire strip and the overheating causes it to break. This is also called as the fuse blowing. A ‘blown’ fuse can be replaced with a new one and the operation of the circuit can be resumed.
Making of a fuse. The terminals that come out of the casing of the fuse are directly connected in the circuit or are connected to wires known as axial leads. These leads can be soldered to a circuit board. For some special fuses, the casing which holds the metal wire strap between two terminals may be filled with sand. This is done so that when the metal wire breaks the circuit, the casing does not shatter with bits of glass or ceramic everywhere.
Characteristics of a Fuse:
Choosing a fuse for the protection of your equipment depends on the circuit and equipment requirement. Below are the characteristics of a fuse which you need to consider.
1. Fast-acting
How quickly the fuse blows once there is a circuit overload is an important consideration while choosing it. You want the fuse to blow before there is any serious damage to other components. A fuse with a high fast-acting characteristic is ideally suited for circuits that cannot withstand even a slight overshoot in the current. They are constructed with a single thin strand of metal wire.
2. Time-delay
A time-delay fuse is used to withstand a high current for a limited amount of time before it breaks the circuit. This is for those circuits where the components can withstand a current overload for a small time. Time-delay fuses are used in circuits that use inductive loads. These fuses use a thick filament or coiled wire so that it does not break at slight overcurrents.
3. Breaking CapacityBreaking capacity refers to the ability of the outer casing of the fuse to remain intact or contain physical damage when the fuse blows. A glass fuse usually has a low breaking capacity while a ceramic fuse will have a higher breaking capacity. Ceramic casings are filled with silica or sand to further increase the breaking capacity.
4. Thermal Considerations
While choosing a fuse, the thermal conditions are an important consideration. Ambient temperature and heat rise need to be taken into account.
Fuse Holders.
Fuse holders are predesigned compartments that can be attached to the equipment. They are made to house fuses of different sizes. A fuse holder usually works in conjunction with a fuse carrier. The fuse carrier is the part which is actually attached to the fuse and then it is connected to the holder so that the assembly of the fuse is complete.
Bulgin manufactures efficient Fuse Holders that adhere to worldwide safety standards. They are made from flame-retardant materials and provide a high degree of protection.
To view the full catalogue of connectors and all other products please visit the Bulgin Website.