Fuse (explosives)

In an explosive, pyrotechnic device or military munition, a fuse (or fuze) is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately. However, when being specific (and in particular in a military context), the term fuse, describes a simple pyrotechnic initiating device, like the cord on a firecracker whereas the term fuze is sometimes used when referring to a more sophisticated ignition device incorporating mechanical and/or electronic components, such as a proximity fuze for an M107 artillery shell, magnetic/acoustic fuze on a sea mine, spring-loaded grenade fuze,pencil detonator or anti-handling device.

History

The simplest form of fuse is the burning fuse, believed to date back to the 10th century and originating in China. This simple fuse consisted of lightweight paper filled with loose gunpowder, and served as a means of delaying ignition in fireworks. This simple form of burning fuse can still be found today in many modern pyrotechnics. A version of this simple fuse is called visco fuse, and consists of the burning core coated with wax or lacquer for durability and water resistance. The commercial and military version of a burning fuse referred to as safety fuse (invented by William Bickford) is a textile tube filled with combustible material and wrapped to prevent external exposure of the burning core. Safety fuses are used to initiate the detonation of explosives through the use of a blasting cap.

Fuse

Fuse or fuze may refer to:

Devices

Computing

Science

Fuse (electrical)

In electronics and electrical engineering, a fuse (from the French fusée, Italian fuso, "spindle") is a type of low resistance resistor that acts as a sacrificial device to provide overcurrent protection, of either the load or source circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, interrupting the circuit that it connects. Short circuits, overloading, mismatched loads, or device failure are the prime reasons for excessive current. Fuses can be alternative to circuit breakers.

A fuse interrupts an excessive current so that further damage by overheating or fire is prevented. Wiring regulations often define a maximum fuse current rating for particular circuits. Overcurrent protection devices are essential in electrical systems to limit threats to human life and property damage. The time and current operating characteristics of fuses are chosen to provide adequate protection without needless interruption. Slow blow fuses are designed to allow harmless short term currents over their rating while still interrupting a sustained overload. Fuses are manufactured in a wide range of current and voltage ratings to protect wiring systems and electrical equipment. Self-resetting fuses automatically restore the circuit after the overload has cleared, and are useful in environments where a human replacing a blown fuse would be difficult or impossible, for example in aerospace or nuclear applications.

Fuse (hydraulic)

In hydraulic systems, a fuse (or velocity fuse) is a component which prevents the sudden loss of hydraulic fluid pressure. It is a safety feature, designed to allow systems to continue operating, or at least to not fail catastrophically, in the event of a system breach. It does this by stopping or greatly restricting the flow of hydraulic fluid through itself if the flow exceeds a threshold.

The term "fuse" is used here in analogy with electrical fuses which perform a similar function.

Hydraulic systems rely on high pressures (usually over 7000 kPa) to work properly. If a hydraulic system loses fluid pressure, (burst hydraulic hose) it will become inoperative and components such as actuators may collapse. This is an undesirable condition in life-critical systems such as aircraft or heavy machinery particularly forklifts. Hydraulic fuses help guard against catastrophic failure of a hydraulic system (for instance, by line breakage or component failure) by automatically isolating the defective branch.