Additional Information

WHY FILTER...

EMI:  Electro-magnetic interference
RFI:  Radio frequency interference (same as above)

EMC: ELECTROMAGNETIC COMPATABILITY

The increased use of electrical and electronic equipment throughout the world has resulted in significant problems with electromagnetic interference (EMI), the presence of unwanted electrical signals affecting the operation of other devices. To combat this problem, standards for Electromagnetic Compatibility for wide range of electrical and electronic equipment are now being enforced in Australia and in many other countries.

EMI can travel by conduction along power or signal cables, and also by radiation through the air. Radiation can be substantially reduced by earthed metal screening / shields with a minimum of openings. Conduction of electrical ‘noise’ via power cables can only be prevented by the use of AC mains power filters. Filters allow low frequency mains current (50Hz in Australia) to flow freely, but suppresses the higher frequency interference signals which would otherwise cause unacceptable EMI problems.


SPECIFY A FILTER

Specifying of a power filter includes:

Voltage rating:  Normally 250vAC 50/60Hz, covering all common AC mains voltages from 100 to 250 volt. Note that three-phase 500 volt filters are also available.

Current Rating:  This must at least equal to the load current, but the most effective filtering is obtained by close matching of filter rating to load. Arlin’s filters cover 1A – 160A.

Mounting Styles: select from:
1. IEC basic inlet filter
2. IEC combination switched, fused, etc.
3. Chassis mount
4. PCB mount

Attenuation:  The effectiveness of a filter is indicated by the attenuation measured in decibels (dB) as a function of frequency; greater dB means better filtering. Attenuation curves are shown for each product in this catalogue, for a 50 Ohm load and source impedance.
Normal mode (symmetric or horizontal) attenuation is from line to line (active to neutral).  Common mode (asymmetric or vertical) attenuation is from lines to earth. Both are significant  in EMI rejection.

Approvals:  Where applicable, filters offered by Arlin have a wide range of approvals from authorities in Europe and North America. Approval file numbers for each product are available on application. The use of an approved filter is a significant step to obtaining international safety approval on a complete product.

STANDARDS
A number of standards exist for EMC of electrical equipment. Details are available from Standards Australia or from Australian Communications Authority offices. Some Australian standards are listed below:

Equipment	AS/NZS Standard
Motor driven & thermal appliances & tools	1044
Lighting	4051
Audio & TV equipment	1053
I.T. equipment	3548
Industrial, scientific & medical equipment	2064 1/2
Generic Emission Standard	4251.1

Testing to these standards is performed by a number of laboratories throughout Australia. Names of accredited test laboratories are available from the Australia communications Authority.