Can capacitors explode?
21152701#28
High-voltage capacitors may catastrophically fail when subjected to voltages or currents beyond their rating, or as they reach their normal end of life. Dielectric or metal interconnection failures may create arcing that vaporizes dielectric fluid, resulting in case bulging, rupture, or even an explosion. Capacitors used in RF or sustained high-current applications can overheat, especially in the center of the capacitor rolls. Capacitors used within high-energy capacitor banks can violently explode when a short in one capacitor causes sudden dumping of energy stored in the rest of the bank into the failing unit. High voltage vacuum capacitors can generate soft X-rays even during normal operation. Proper containment, fusing, and preventive maintenance can help to minimize these hazards.
Applications of capacitors
4932111#148
Capacitors may catastrophically fail when subjected to voltages or currents beyond their rating, or as they reach their normal end of life. Dielectric or metal interconnection failures may create arcing that vaporizes the dielectric fluid, resulting in case bulging, rupture, or even an explosion. Capacitors used in RF or sustained high-current applications can overheat, especially in the center of the capacitor rolls. Capacitors used within high-energy capacitor banks can violently explode when a short in one capacitor causes sudden dumping of energy stored in the rest of the bank into the failing unit. High voltage vacuum capacitors can generate soft X-rays even during normal operation. Proper containment, fusing, and preventive maintenance can help to minimize these hazards.
Capacitor
1342988#33
At the beginning of the 1990s, some Japanese manufacturers started the development of a new, low-ohmic water-based class of electrolytes. Water, with its high permittivity of ε = 81, is a powerful solvent for electrolytes, and possesses high solubility for conductivity-enhancing concentrations of salt ions, resulting in significantly improved conductivity compared to electrolytes with organic solvents like GBL. But water will react quite aggressively and even violently with unprotected aluminum, converting metallic aluminum (Al) into aluminum hydroxide (Al(OH)), via a highly exothermic reaction that gives off heat, causing gas expansion that can lead to an explosion of the capacitor. Therefore, the main problem in the development of water-based electrolytes is achieving long-term stability by hindering the corrosive action of water on aluminum.
Capacitor plague
337065#15
The flux compression generator is one alternative to capacitors. When fired, it creates a strong electromagnetic pulse, which is inductively coupled into one or more secondary coils connected to the bridge wires or slapper foils. A low energy density capacitor equivalent to a compression generator would be roughly the size of a soda can. The energy in such a capacitor would be ·C·V, which for the above-mentioned capacitor is 12.5 J. (By comparison, a defibrillator delivers ~200 J from 2 kV and perhaps 20 µF. The flash-strobe in a disposable camera is typically 3 J from a 300 V capacitor of 100 µF.)
Exploding-bridgewire detonator
337065#14
The EBW and the slapper detonator are the safest known types of detonators, as only a very high-current fast-rise pulse can successfully trigger them. However, they require a bulky power source for the current surges required. The extremely short rise times are usually achieved by discharging a low-inductance, high-capacitance, high-voltage capacitor (e.g., oil-filled, Mylar-foil, or ceramic) through a suitable switch (spark gap, thyratron, krytron, etc.) into the bridge wire. A very rough approximation for the capacitor is a rating of 5 kilovolts and 1 microfarad, and the peak current ranges between 500 and 1000 amperes. The high voltage may be generated using a Marx generator. Low-impedance capacitors and low-impedance coaxial cables are required to achieve the necessary current rise rate.
Exploding-bridgewire detonator
21152701#6
Large capacitor banks (reservoirs) are used as energy sources for the exploding-bridgewire detonators or slapper detonators in nuclear weapons and other specialty weapons. Experimental work is under way using banks of capacitors as power sources for electromagnetic armour and electromagnetic railguns or coilguns.
Applications of capacitors
4932111#123
Large capacitor banks (reservoir) are used as energy sources for the exploding-bridgewire detonators or slapper detonators in nuclear weapons and other specialty weapons. Experimental work is under way using banks of capacitors as power sources for electromagnetic armour and electromagnetic railguns and coilguns.
Capacitor
44391001#5
The basic components needed for the exploding wire method are a thin conductive wire and a capacitor. The wire is typically gold, aluminum, iron or platinum, and is usually less than 0.5 mm in diameter. The capacitor has an energy consumption of about 25 kWh/kg and discharges a pulse of charge density 10 - 10 A/mm, leading to temperatures up to 100,000 K. The phenomenon occurs over a time period of only 10 - 10 seconds.
Exploding wire method
34469840#2
When the capacitor is discharging, the strength of the electric field is decreasing and the common orientation of the molecular dipoles is returning to an undirected state in a process of relaxation. Due to the hysteresis, at the zero point of the electric field, a material-dependent number of molecular dipoles are still polarized along the field direction without a measurable voltage appearing at the terminals of the capacitor. This is like an electrical remanence. The oriented dipoles will be discharged spontaneously over time and the voltage at the electrodes of the capacitor will decay exponentially. The complete discharge time of all dipoles can be days to weeks depending on the material. This "reloaded" voltage can be retained for months, even in electrolytic capacitors, caused by the high insulation resistance in common modern capacitor dielectrics. The discharge of a capacitor and the subsequent reloading can be repeated several times.
Dielectric absorption
4397993#2
The decoupling capacitor works as the device’s local energy storage. The capacitor is placed between power line and ground to the circuit that current is to be provided. According to capacitor equation, formula_1, voltage drop between power line and ground results in current draw out from the capacitor to the circuit and when capacitance "C" is large enough, sufficient current is supplied to maintain an acceptable range of voltage drop. To reduce the effective series inductance, small and large capacitors are often placed in parallel; commonly positioned adjacent to individual integrated circuits. The capacitor stores a small amount of energy that can compensate for the voltage drop in the power supply conductors to the capacitor.
Decoupling capacitor
4932111#53
The breakdown voltage is critically affected by factors such as the geometry of the capacitor conductive parts; sharp edges or points increase the electric field strength at that point and can lead to a local breakdown. Once this starts to happen, the breakdown quickly tracks through the dielectric until it reaches the opposite plate, leaving carbon behind and causing a short (or relatively low resistance) circuit. The results can be explosive as the short in the capacitor draws current from the surrounding circuitry and dissipates the energy. However, in capacitors with particular dielectrics and thin metal electrodes shorts are not formed after breakdown. It happens because a metal melts or evaporates in a breakdown vicinity, isolating it from the rest of the capacitor.
Capacitor