Building Schaffner FN410 Line Filter - Inductors Connected to Ground

  • Thread starter Thread starter Kilamir
  • Start date Start date
  • Tags Tags
    Filter Line
Click For Summary
SUMMARY

The discussion centers on building the Schaffner FN410 line filter using discrete components. The original datasheet does not specify the inductance values for inductors connected to ground, which are believed to mitigate common-mode noise. However, it is clarified that the FN410 design does not typically include inductors connected to ground, as the filter topology relies on series inductors and parallel capacitors (X and Y capacitors) for effective lowpass filtering. The X capacitor aids in differential filtering, while the Y capacitors contribute to both common-mode and additional differential filtering.

PREREQUISITES
  • Understanding of filter design principles, specifically lowpass filters.
  • Familiarity with Schaffner FN410 specifications and datasheet interpretation.
  • Knowledge of common-mode and differential-mode noise in electrical circuits.
  • Basic electronics components, including inductors and capacitors.
NEXT STEPS
  • Research the role of X and Y capacitors in filter design.
  • Study common-mode noise reduction techniques in electrical circuits.
  • Explore alternative line filter designs and their component specifications.
  • Learn about the impact of inductance values on filter performance.
USEFUL FOR

Electrical engineers, hobbyists building EMI filters, and anyone involved in designing or optimizing line filters for noise reduction.

Kilamir
Messages
1
Reaction score
0
I am trying to build the Schaffner line filter FN410 out of discrete parts. The datasheet for that part can be seen here:

http://www.schaffner.com/corporate/en/register_log.asp?language_id=12&fN=http%3A%2F%2Fwww%2Eschaffner%2Ecom%2Fcomponents%2Fen%2F%5Fpdf%2FDatasheet+FN410+e+6%2Epdf

Anyways, they list all the values for the inductors and capacitors that they use in the circuit except for the inductors connected to ground. I believe they help against incoming common-mode noise. Does anybody have an idea what inductance should be use for those inductors?

Thanks in advance!
 
Last edited by a moderator:
Engineering news on Phys.org
Kilamir said:
I am trying to build the Schaffner line filter FN410 out of discrete parts. The datasheet for that part can be seen here:

http://www.schaffner.com/corporate/en/register_log.asp?language_id=12&fN=http%3A%2F%2Fwww%2Eschaffner%2Ecom%2Fcomponents%2Fen%2F%5Fpdf%2FDatasheet+FN410+e+6%2Epdf

Anyways, they list all the values for the inductors and capacitors that they use in the circuit except for the inductors connected to ground. I believe they help against incoming common-mode noise. Does anybody have an idea what inductance should be use for those inductors?

Thanks in advance!

Welcome to the PF, Kilamir. It's a great place.

I don't see any inductors to ground in the filter datasheet schematic, and inductors are not usually connected to ground in this type of filter anyway. In general, the topology will be some series high impedances (the inductors) and some parallel low impedances (the X and Y capacitors) to provide the lowpass filtering characteristics (for both common mode and differential mode).

In the schematic for this filter, there is an X cap for the differential lowpass filter characteristic (in conjunction with the inductors), and two Y caps for the common-mode lowpass filter characteristic. Of course, the Y caps also provide some additional differential LPF contribution as well (Quiz Question -- why?). Does that help?
 
Last edited by a moderator:

Similar threads

Problems driving a large display with a transistor
  • · Replies 6 ·
Replies
6
Views
4K