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Hi.
I cant seem to source any Belling Lee 250v mains filters anywhere, so have been thinking of constructing one.
The things I am unsure of are detailed in the attached picture of a belling lee diagram label
. Could some one please take a look
and help me out.
I am surprised that you cannot find a filter to buy.
What are the important parameters for your application? Voltage, Current, Attenuation ?
If you were to build your own, I think that 275v X and Y capacitors should be OK.
The 1 meg resistor will not dissipate much power, it just needs to have a rating of 250v or greater.
It is just there to ensure that the capacitors do not hold a residual charge when disconnected from the mains.
The inductors, not too sure about them.
I think that the mix will be a lossy high Al (mu ?) ferrite.
As for the windings, there may actually be too different forms in the complete filter.
One to to suppress common mode noise, and one to suppress series mode noise.
Hi thanks JimB & ronsimpson for your help so far. The filter is going to be used as mains filter for Ham shack mains feed. Hopefully will suppress mains noise from the house wiring from 1 to 30Mhz. I wont be drawing more than 1200 watts in total from the shack devices , Pc, printer, monitor, 100w transceiver ect.
JimB Yes these Belling Lee filters are hard to source now .I take it that I can use a 1m 2w 500v resistor ?.
Ronsimpson I thank you for the pictures of the chokes , I think you guessed that I learn more quickly from pictures than words based on my post pic above.
So I just wait the answer now on the 500v resistor.
You need a resistor that is rated for the peak voltage.
You can use two lower voltage resistors. (three or four)
When you get capacitors, X is for across the power line and Y is from Line to ground. They are rated for power line and should not cause fires if things really go wrong.
Too bad you are not next door. I have the parts. Almost what I do.
That is a very good filter. You could probably be OK with a CLC filter. (not the CLCLC)
If I was going to build this I have copper tape, that I cut and stick on purf board. The layout is important.
Hi just a quick rough layout drawing for my intended pcb. How does this layout look.
Not sure what you mean about 3/4 resistors do you mean in parallel ?.
Forgot to add , all components on pcb will be placed into a tin case earthed by the tabs. And then completely
resin potted. Not sure though if the chokes being 500 uH instead of 450 uH will throw the HPF out of wack, regarding freq range suppression ?.
I suppose I could unwind maybe 1 turn on each though to get nearer 450 uH
gee I must be tired. How the hell did I do that. I must remember not to build and test this pcb at gone midnight.
I have quickly corrected it now , will do a more tidy pcb tomorrow.
Thanks my friend for your time and help so far.
Regards.
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