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Harmonics Today

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What is Harmonics?

What is Harmonics?

Harmonic distortion is a form of electrical pollution that can cause problems if the sum of the harmonic currents increases above certain limits. A harmonic current is one with a frequency at a multiple of the fundamental frequency;For example, a 250Hz current on a 50Hz network is the 5th harmonic. The 250Hz current represents energy that cannot be used by devices on the network. This will therefore convert to heat.

Non-linear loads such as PC’s, Flourescent lighting, and UPS systems create harmonic currents and voltages.

Harmonics can be reduced by either modifications to the drive system in place or by using external filtering. The current harmonics depend on the drive constuction and load.

Factors that increase harmonics include
Large motor compared to the supply transformer.
Higher motor load

Factors that decrease harmonics include
Greater DC or AC inductance
Higher number of pulses in the rectifier

Factors that decrease voltage harmonics caused by the harmonic currents can be
Larger transformer
Lower transformer impedance
Higher short circuit capacity of supply.

Contact us to discuss your applications. We can provide harmonic surveys at your site and give you full analysis of your existing and future site requirements.

Harmonic Surveys

New harmonics rules affect every consumer connected to the public electricity supply, including domestic and commercial consumers, as well as industrial users. In most instances, We are able to carry out detailed harmonic surveys of both harmonic currents and voltages using proprietary equipment.

An associated computer program will the be used to interpret site results. Analysis of the findings will confirm a customer solution to ensure current legislation compliance.


EMC assessment

We understand electromagnetic compatibility issues and its engineers can help you follow the basic principles to ensure the EMC compatibility of your drive installation.

Contact us to discuss your requirements

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