Yes, it is has a large inductance but the size is not so big because it is wound on a Nanoperm core. However it must saturate or have a high self-capacitance to still let some of that noise through.
Oh.. that's a common mode choke. Only useful when you run a twisted pair through it (or, it doesn't matter that the wires be twisted together, they can be separate -- as long as they are wound on the core the same direction).
Those cores saturate with a few mA so you're getting bupkis if it's not being used as a CMC.
Common mode is only 42mVp-p.
Not horrific, but still well outside of FCC limits.
No, the controller itself is the load. It has 8 CPUs that draw 20A when fully tasked.
Oh.. well, that's a lot of control. That's not what comes to mind when I hear "controller". You can control a small corner of the internet with that kind of CPU power...
I guess I could wind my own choke that has less inductance with the turns far apart so it also has a small self-capacitance ...but my LCR meter shows that these large 10mF electrolytic caps have above an Ohm of ESR at 100kHz so are you sure they will do me any good ?
Would Tantalums be better? I heard good stuff about the ESR of polypropylene film caps @ 100kHz, too... Is there any truth to it?
You need a lot of film caps to do the job (20uF+), but that works. Tantalum, no, sooner or later it will catch fire, with that kind of available current.
Either your caps are toast, or your ESR meter stinks -- whatever the case, a proper, say, 25V 2200uF low-ESR electrolytic should be in the 10s of milliohms, just fine for this.
Same kind of thing should be found inside the power supply too, if you care to snoop around inside it. Although with that much ripple, I'd be worried how long it's going to last, and if it's made with poor caps in the first place.
For the inductor, this is a perfect application for those powdered iron toroids you find in ATX supplies (yellow-white or green-blue core), if you've parted out any.
Tim