Overheating (electricity)

Failed IC in a laptop. Wrong input voltage has caused massive overheating of the chip and melted the plastic casing.

Overheating is a phenomenon of rising of temperature in an electric circuit (or portion of a circuit). Overheating causes potential damage to the circuit components, and can cause fire, explosion, or injury. Damage caused by overheating is commonly irreversible; i.e. the only way to repair is to replace some components.

Causes

On overheating, the temperature of the part rises above the operating temperature. Overheating can take place

  1. if heat is produced in more than expected amount (such as in cases of short-circuits, or applying more voltage than rated), or
  2. if heat dissipation is poor, so that normally produced waste heat 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 to an equilibrium of heat accumulation vs. dissipation, at a much higher temperature than expected.

Preventive measures

Use of circuit breaker or fuse

Circuit-breakers placed at different portions of 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 kind of widely used circuit breaker, that involves direct effect of Joule-overheating. A fuse is always placed in series with the path of current it will affect. Depending upon work, inside a fuse, there is a narrow (often a hairline) wire of definite-material, in the fuse. When more-than expected current flows through the fuse; the fuse-wire overheats (melts) and "opens" the circuit. In some gadgets, more than one

Use of heat-dissipating systems

Many ventilator holes or slits kept on the box of equipments. Heat sinks (heat-radiating metallic objects) attached with some-portions of the circuit that produce more heat/ more vulnerable to heat. often, fans are required. Some high-voltage instruments kept immersed in oil. In some cases, to remove unwanted heat, some cooling-system like air-condition or refrigerating-heat-pumps may be required.

Control within circuit-design

Sometimes special circuits built for purpose of sensing the temperature or voltage status, and thereafter controlling these variables. In these circuits, Thermistors (Temperature dependent resistors), VDR (voltage-dependent resistors), thermostat (that switches off the circuit at higher-temperature), Sensors (such as infrared-thermometers), etc. used to modify the current upon different conditions like circuit-temperature and input voltage.

Proper manufacture

For a certain definite purpose in a definite electrical equipment or a portion of it, definite type and size of materials (for boards,wires, insulators) 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, on the wire-joints, appropriate type of electrical connectors and mechanical fasteners used.

See also

References

    Sources

    1. ↑ http://www.ufba.org.nz/images/documents/hazardsandsafeguards.pdf
    2. ↑ "Classification of Electrical Overheating Modes - Electro-Mechanical Recertifiers, Inc". Retrieved 27 August 2016.
    3. ↑ ElectroTechnik. "What are the reasons for transformer overheating?". Retrieved 27 August 2016.
    4. ↑ "The Basics of Electrical Overheating". Retrieved 27 August 2016.
    5. ↑ http://www.testequipmentdepot.com/application-notes/pdf/power-quality/case-study-the-overheating-transformer_an.pdf
    6. ↑ http://protectowire.com/documents/ds-8899.pdf
    7. ↑ http://www.mirusinternational.com/downloads/hmt_faq10.pdf
    8. ↑ http://www.learnabout-electronics.org/Downloads/ac_theory_module11.pdf
    9. ↑ "Power Transformers". Retrieved 27 August 2016.
    10. ↑ http://sound.whsites.net/xfmr.htm
    11. ↑ http://sound.whsites.net/xfmr-6.jpg
    12. ↑ "Top 14 Reasons Electrical Service Installations Get Red Tagged". Retrieved 27 August 2016.
    13. ↑ http://ecmweb.com/site-files/ecmweb.com/files/uploads/2016/03/Electrical-Service-Meltdown-6.jpg
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