emission control, ltd.
Frequently Asked Questions (FAQ)

 
Emission Control

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Conducted EMI Testing

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How will the revised FCC Part 15 rules affect my equipment?

Do Emission Control's EMI/RFI filters carry the CE Marking?

Does Emission Control have low leakage medical version filters?

What is the lifespan of a filter under normal conditions and use?

What is the best way to hook up my new Emission Control filter?

The over-voltage condition on my application exceeds the voltage rating of the filter I am considering, is this a problem?

I have a three-phase application that is operating at a higher current level than 75 amps. Can Emission Control help?

What is the proper way to parallel Emission Control, Ltd. EMI/Filters?

Will paralleling two filters affect the insertion loss?




How will the revised FCC Part 15 rules affect my equipment?

The FCC Part 15 conducted emission limit was extended down from 450 KHz. to 150 KHz. which now brings it into line with european EN55022 guidelines. All class "A" and class "B" digital devices built after July 10, 2005 must comply with the new standard. What this means is that your equipment may require a larger filter.

The first thing to do is review your existing conducted emission compliance data. If your FCC data was recorded down to 150 Khz. you will know whether or not your OK. If your equipment was tested for european compliance, then it was tested down to 150 KHZ. and you can use that data to show compliance.

If FCC data was only taken to 450 KHZ., then you will have to have the equipment re-tested. If the existing data shows a 6 db or larger safety margin, you will probably get by with your existing powerline filter. If you don't have that safety margin you may still pass; but if you don't, be aware that you may have to move up from a single stage filter to a two stage unit.


Do Emission Control's EMI/RFI filters carry the CE Marking?

Yes, many of Emission Control's broad range of three-phase and single phase filters are labeled with the CE mark. This is done as a marketing service to help you solve your application problems. RFI powerline filters are components and therefore are not covered by the CE requirements, but they are used in electronic systems to meet EMC specifications.

Most filters carry the major agency approvals: UL, TUV, CSA and VDE. It is not mandatory for the RFI filter to be approved by a European safety agency, but an approval by a safety agency such VDE in Germany, does eliminate delays in testing the RFI filter for safety requirements at the system level.


Does Emission Control have low leakage medical version filters?

Most three-phase and single-phase filters offered by Emission Control are available in low-leakage medical versions. Contact Emission Control to get more information on their low-leakage medical version filters.


What is the lifespan of a filter under normal conditions and use?

The Emission Control filter is designed for a 10-12 year MTBF under normal use. However, our records indicate that many filters have been working continuously for more than 20 years.


What is the best way to hook up my new Emission Control filter?

Many times when a filter selection is based solely on insertion loss, the result is a lower level of performance than anticipated and at a higher cost. The extremely high insertion loss numbers are rarely achieved in actual installations compared to the data sheet measurements made under laboratory test conditions. Select a filter based on both the application and the EMI specification. To gain maximum benefit, pay attention to the installation of the filter by following these guidelines:

1.) Maintain a RF Ground: Mount the filter as close as possible to the EMI source. The filter and the EMI source must be mounted on a common ground plane in order for the filter to bypass the EMI currents to ground and return them to the source. It is imperative that this ground connection be a low impedance at RF frequencies. Grounding the filter case to the source equipment thru a two-foot length of 12-gauge wire is totally inadequate. Mounting both within inches of each other on a common metal plate or chassis will insure adequate grounding well into the 30 MHz. range. If the filter is to be mounted in a separate enclosure, then the two enclosures must be connected together thru a short section of rigid metal conduit thru which the wiring is run. In this case, we are relying on the conduit to provide the low impedance ground connection.

2.) Isolate the LINE and LOAD Wiring: Do not under any circumstances, run both LINE and LOAD wiring thru a common conduit or cable harness. The resulting inductive and capacitive coupling will deteriorate the filter's performance. Keep the LINE and LOAD wires of the filter separated as far as possible from each other and route this wiring as close as possible to the chassis or ground plane to maintain isolation.

3.) Guard against Radiated Noise: Long wire runs carrying EMI currents will act as antennas radiating the noise to nearby circuitry. If these signals are picked up by the wiring before the filter, it will appear that the filter is not adequately removing the conducted EMI when in fact what we are seeing are the effects of the radiated EMI. In the case of variable speed motor drives, the wiring between the drive and the motor can be the source of interference well into the AM radio band. If a special output filter is not used at the drive to lower the emissions, then these lines must be shielded. Shielding can be accomplished most inexpensively by running the wires in solid metal conduit. Shielded power cable can be used at a considerably higher cost.


The over-voltage condition on my application exceeds the voltage rating of the filter I am considering, is this a problem?

The filter will still work; but due to safety and legal concerns, one should only consider this with a line voltage no greater than 110% of the filter's voltage rating.

There are several additional factors to consider:
   1. The filter's expected life will be less than the designed MTBF of 10-12 years.
   2. The filter will not be recognized or approved by the safety agencies at this higher line voltage.
   3. The capacitors will eventually fail. When this happens, it will probably blow a circuit breaker.


I have a three-phase application that is operating at a higher current level than 75 amps. Can Emission Control help?

A wide variety of EMI/RFI filters are available from Emission Control Ltd. including "L" type and "T" type for three phase in either "delta" or "wye" configurations, plus single-phase filters. Ampere rating range from 10 amps to 75 amps, while voltage ratings of up to 600 volts are available. Occasionally, there are requirements to provide filtering for equipment operating at significantly higher current levels. By utilizing our FL Series of high current filters, filtering for applications up to 300 amps can be handled.


What is the proper way to parallel Emission Control, Ltd. EMI/Filters?

1. Determine the normal operating current that will be flowing through the filter network in RMS amperes.
2. Determine rating and quantity of filters required to carry the RMS current rating of the system. (100 amps = two 60 ampere filters).
3. Precut eight leads for each delta type filter to be parallel connected, and ten leads for each wye type filter. LEADS MUST ALL BE THE SAME LENGTH.
4. Connect all like terminals from each filter to a point on an external terminal block using ring type lugs on each end of the paralleling wires. Make proper connection lug to wire by crimping and then soldering. SEE CONNECTION DIAGRAM.
5. Make external system connections to terminal blocks on both the line side and load side of the filter, (see diagram 1). Make certain that all connections are tightened properly. NOTE: ALL PARALLELING WIRES MUST BE THE EXACT SAME LENGTH TO ASSURE THE MULTIPLE CONNECTED FILTERS SHARE THE TOTAL CURRENT EQUALLY. IF UNITS DO NOT SHARE THIS CURRENT EQUALLY, EXCESSIVE CURRENT MAY FLOW THROUGH ONE OR MORE FILTERS CAUSING ALL OR SOME OF THE FILTERS TO FAIL.


Will paralleling two filters affect the insertion loss?

Paralleling two filters of the same current rating to double the effective current rating will add 6 db to the insertion loss curve for the single filter.