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'''Copper loss''' is the term often given to [[heat]] produced by [[electrical current]]s in the [[Electrical conductor|conductor]]s of [[transformer]] windings, or other electrical devices. Copper losses are an undesirable transfer of [[energy]], as are [[core loss]]es, which result from [[induced current]]s in adjacent components. The term is applied regardless of whether the windings are made of [[copper]] or another conductor, such as [[aluminium]]. Hence the term '''winding loss''' is often preferred. The term [[load loss]] is closely related but not identical, since an unloaded transformer will have some winding loss. | |||
Copper losses result from [[Joule heating]] and so are also referred to as "I squared R losses", in reference to [[Joule's first law|Joule's First Law]]. This states that the energy lost each [[second]], or [[Power (physics)|power]], increases as the [[square (algebra)|square]] of the current through the windings and in [[proportionality (mathematics)|proportion]] to the [[electrical resistance]] of the conductors. | |||
:<math>\mbox{Copper Loss} \propto I^2 \cdot R</math> | |||
where I is the current flowing in the conductor and R the resistance of the conductor. With I in [[ampere]]s and R in ohms, the calculated power loss is given in [[watt]]s. | |||
Joule heating has a [[coefficient of performance]] of 1.0, meaning that every 1 watt of electrical power is converted to 1 Joule of heat. Therefore, the energy lost due to copper loss is: | |||
:<math>\mbox{Copper Loss} = I^2 \cdot R \cdot t</math> | |||
where t is the time in [[second]]s the current is maintained. | |||
With high-frequency currents, winding loss is affected by [[Proximity effect (electromagnetism)|proximity effect]] and [[skin effect]], and cannot be calculated as simply. | |||
For low-frequency applications, the power lost can be minimized by employing conductors with a large cross-sectional area, made from low-[[resistivity]] metals. | |||
{{Main|Copper in energy efficient motors}} | |||
Among other measures, the electrical energy efficiency of a typical industrial [[induction motor]] can be improved by reducing the electrical losses in the [[stator]] windings (e.g., by increasing the cross-sectional area of the conductor, improving the winding technique, and using materials with higher electrical conductivities, such as [[Copper in energy efficient motors|copper]]). | |||
==See also== | |||
* [[Iron loss]] | |||
* [[Copper in energy efficient motors]] | |||
==External links== | |||
* [http://www.articleworld.org/index.php/Copper_loss Reduction of copper losses] | |||
[[Category:Transformers (electrical)]] | |||
[[Category:Electrical engineering]] | |||
{{electric-stub}} | |||
Revision as of 12:44, 1 February 2014
Copper loss is the term often given to heat produced by electrical currents in the conductors of transformer windings, or other electrical devices. Copper losses are an undesirable transfer of energy, as are core losses, which result from induced currents in adjacent components. The term is applied regardless of whether the windings are made of copper or another conductor, such as aluminium. Hence the term winding loss is often preferred. The term load loss is closely related but not identical, since an unloaded transformer will have some winding loss.
Copper losses result from Joule heating and so are also referred to as "I squared R losses", in reference to Joule's First Law. This states that the energy lost each second, or power, increases as the square of the current through the windings and in proportion to the electrical resistance of the conductors.
where I is the current flowing in the conductor and R the resistance of the conductor. With I in amperes and R in ohms, the calculated power loss is given in watts.
Joule heating has a coefficient of performance of 1.0, meaning that every 1 watt of electrical power is converted to 1 Joule of heat. Therefore, the energy lost due to copper loss is:
where t is the time in seconds the current is maintained.
With high-frequency currents, winding loss is affected by proximity effect and skin effect, and cannot be calculated as simply.
For low-frequency applications, the power lost can be minimized by employing conductors with a large cross-sectional area, made from low-resistivity metals.
Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. Among other measures, the electrical energy efficiency of a typical industrial induction motor can be improved by reducing the electrical losses in the stator windings (e.g., by increasing the cross-sectional area of the conductor, improving the winding technique, and using materials with higher electrical conductivities, such as copper).