Overheating is a phenomenon of rising temperatures in an

electrical circuit An electrical network is an interconnection of electrical components (e.g., batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage source ...

. Overheating causes damage to the circuit components and can cause fire, explosion, and injury. Damage caused by overheating is usually irreversible; the only way to repair it is to replace some components.

Causes

When overheating, the temperature of the part rises above the

operating temperature An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the de ...

. Overheating can take place: *if heat is produced in more than expected amount (such as in cases of short-circuits, or applying more voltage than rated), or *if heat dissipation is poor, so that normally produced

waste heat Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utilit ...

does not drain away properly. Overheating may be caused from any accidental fault of the circuit (such as short-circuit or spark-gap), or may be caused from a wrong design or manufacture (such as the lack of a proper heat dissipation system). Due to accumulation of heat, the system reaches an equilibrium of heat accumulation vs. dissipation at a much higher temperature than expected.

Preventive measures

Use of circuit breaker or fuse

Circuit-breakers can be placed at portions of a circuit in series to the path of current it will affect. If more current than expected goes through the circuit-breaker, the circuit breaker "opens" the circuit and stops all current. A fuse is a common type of circuit breaker that involves direct effect of Joule-overheating. A fuse is always placed in series with the path of current it will affect. Fuses usually consist of a thin strand of wire of definite-material. When more that the rated current flows through the fuse, the wire melts and breaks the circuit.

Use of heat-dissipating systems

Many systems use ventilation holes or slits kept on the box of equipment to dissipate heat.

Heat sink A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, ...

s are often attached to portions of the circuit that produce most heat or are vulnerable to heat. Fans are also often used. Some high-voltage instruments are kept immersed in oil. In some cases, to remove unwanted heat, a cooling system like

air conditioning Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...

or refrigerating

heat-pump A heat pump is a device that can heat a building (or part of a building) by transferring thermal energy from the outside using a refrigeration cycle. Many heat pumps can also operate in the opposite direction, cooling the building by removing h ...

s may be required.

Control within circuit-design

Sometimes, special circuits are built for the purpose of sensing and controlling the temperature or voltage status. Devices such as

thermistor A thermistor is a type of resistor whose resistance is strongly dependent on temperature, more so than in standard resistors. The word thermistor is a portmanteau of ''thermal'' and ''resistor''. Thermistors are divided based on their conduction ...

s, voltage-dependent resistors,

thermostat A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint (control system), setpoint. Thermostats are used i ...

s and sensors such as

infrared thermometer An infrared thermometer is a thermometer which infers temperature from a portion of the thermal radiation sometimes called black-body radiation emitted by the object being measured. They are sometimes called laser thermometers as a laser is use ...

s are used to modify the current upon different conditions such as circuit-temperature and input voltage.

Proper manufacture

For certain purposes in an item of electrical equipment or a portion of it, definite type and size of materials with proper rating for voltage, current and temperature, are used. The circuit resistance never kept too low. Sometimes some parts placed inside the board and box, maintaining a proper distance from each other, to avoid heat damage and short-circuit damage. To prevent short circuit, appropriate types of electrical connectors and mechanical fasteners are used.

Gallery

References

*http://www.ufba.org.nz/images/documents/hazardsandsafeguards.pdf * * * *http://www.testequipmentdepot.com/application-notes/pdf/power-quality/case-study-the-overheating-transformer_an.pdf * *http://www.mirusinternational.com/downloads/hmt_faq10.pdf *http://www.learnabout-electronics.org/Downloads/ac_theory_module11.pdf * *http://sound.whsites.net/xfmr.htm *http://sound.whsites.net/xfmr-6.jpg * *http://ecmweb.com/site-files/ecmweb.com/files/uploads/2016/03/Electrical-Service-Meltdown-6.jpg {{refend Electricity Electrical engineering Electric heating Thermodynamics Safety Fire prevention Fire protection Legal codes