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Few companies look at the consequences of installing floor upon floor of computing equipment until they find they have burnt out transformers and power supplies are failing in large quantities. However, the introduction of the new G5/4 standard which will become mandatory could mean severe penalties for companies who are exporting there problem to others locally on the National Grid.
The world today has numerous sources of Harmonics which can seriously affect the quality of the mains supply.
The typical sources are:- 1) Switched mode power supplies in computers. 2) Variable speed drives 3) Air conditioning 4) Rectifier systems 5) Uninterruptible Power Supplies 6) Lighting 7) Welding
The main problem encountered today is high third harmonic currents flowing in the neutral of the clients site. These high currents are produced by the loads listed above but where as other harmonics tend to cancel each out, the third actually adds in the neutral i.e. you obtain three times the third harmonic phase current. UPS systems have been designed with neutrals 1.75 times the design phase current level to allow for this fact.
These currents can lead to losses being increased by 10% in the main transformer leading to premature transformer failure and high costs wich are rising rapidly with increases in electricity prices.
This problem can be alleviated by proper design, the use of filters or by using electronic cancellation techniques.
KJM Power Consultants can identify these problems and suggest a strategy for their reduction to reasonable operating levels. A simple days survey can be carried out from which problems can be identified and solutions suggested. The survey fee is deductible, in certain circumstances, from the costs of the recommended equipment if the client goes ahead. |
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Harmonics |
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The Polluter Pays! |
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Phone: 01547 530306 Fax: 01547 530128 Email: kjmuttitt@force9.co.uk |
