Top 5 Mistakes in EMI Filter Placement and How to Fix Them
When installing a filter to mitigate electromagnetic interference (EMI), there are some critical EMI filter mistakes to avoid. This guide will go over some of the most common mistakes and how to prevent them from reducing the effectiveness of an EMI filter replacement or new installation.
Input and Output Trace Coupling
One of the main EMI filter mistakes involves placing input and output wires beside or in close proximity to each other, which could limit the filter’s ability to effectively filter out EMI noise. Keeping input and output wires separate will enable reliable filtering. Also, separate control wires from power wires to prevent them from running parallel.
If needed, you can install shielding over wiring to further mitigate the risk of interference from radiated noise.
Poor Grounding/Bonding
Improper grounding and bonding to host equipment can present safety issues while also limiting the efficiency of EMI filter replacements.
When installing your EMI filter, the housing of the filter should maintain direct metal-to-metal contact with the surface it is to be mounted on, ensuring all surfaces are conductive without any insulation, including paint.
If you are using a cabinet or housing made of another material, ground the filter using an incoming safety wire with a short length, and use a flat braid design for any connections coming into contact with metal materials on cabinet frames.
When grounding your EMI filter, remember the difference between a safety ground and an EMI system ground. A safety ground uses a conductor or connection to enable currents to easily travel when a circuit fault occurs, which is why you need something other than a conventional safety ground for these types of systems involving high frequencies.
Here are some additional tips for grounding your EMI filter:
- Flat wires and other types of low-impedance connections can mitigate high-frequency interference more effectively than round wires.
- Ground connections must be of minimal length, but you can maximize surface area with braided and flat connections.
- Remove any paint present on cabinet mounting surfaces to further minimize impedance.
- Remain compliant with all safety regulations, adhering to industry guidance for safe grounding practices.
Incorrect Placement Relative to Noise Sources
Again, make sure the input and output wires have sufficient shielding to prevent interference between them. Generally, when placing your EMI filters, they should be in a location where energy is unable to couple onto pre- and post-filtration locations.
Keep in mind that filters and feedthrough capacitors feature designs for mounting within wall penetrations.
High-Frequency Noise Leakage
Inadequate installation will also permit high-frequency noise leakage. Installing EMI filters close to power entry points, keeping input and output wires away from each other, and minimizing the impedance of ground connections will help prevent noise from getting through and causing interference.
Implement low-leakage EMI filters to simplify grounding and insulation and reduce overall reliance on shielding.
Ignoring Component Coupling/Shielding
Another factor to consider is coupling and shielding. You can keep noise from coupling with wires and other components by routing wires beside the metal surfaces of the cabinet. If needed, add shielding to wires to reduce the risk of radiated noise from interfering with input wires, and make sure both ends of the shielding terminate when they reach the end of the cable to mitigate the risk of leakage at either end.
Contact the Experts at Captor Corp for Reliable EMI Filters
By avoiding these EMI filter mistakes, you can benefit from a high-quality filtering system that keeps equipment working optimally with little to no interference.
If you need high-quality EMI filter replacements for your systems, Captor Corp offers some of the most reliable EMI filter solutions available. If you need protection from power, signal, tempest, or another type of interference, we will match you with the right product.
For more information about our versatile EMI filter products and capabilities, submit a request for information on our website, or contact us today to speak with one of our EMI filtration experts.
