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Re: 120 khz X-10 / INSTEON 'filters' ; was Re: X10 Interference from the Cellet Cellphone Charger



Thanks Jeff. It makes sense that folks interested in a clean X-10/INSTEON
signal would optimize the depth of the notch at 120/121khz.

The 20-amp version of the CORCOM R Series filters that I use

www.econtrol.org\CORCOM R Series schematic.htm

in my air-gap switch and power conditioning unit

www.econtrol.org\power_conditioning.htm

is down 44db at 500khz but only -4 db at 125khz. This should clean up any
X-10/INSTEON 2nd harmonic, but doesn't do much for the fundamental and
lower. I would be better off leaving the 0.22uf caps in place in the
8-component X-10 filters I am adding if my only concern were to attenuate
the X-10/INSTEON fundamental but there's also sub-120khz garbage from triac
dimmers and various switchers so I think I'll leave them in.

Folks looking for a less expensive way to filter small, noisy power
supplies like the Cellet Cellphone charger than the standard
X-10/Leviton/ACT options might consider the smaller (eg) CORCOM filters or
equivalents. The 1 and 3amp versions of the filter series I cited are
spec'd as 25-30 db down at 125khz and so should do a good job cleaning up
in-band X-10/INSTEON noise. They are typically available as New Old Stock
for a couple of bucks on eBay. I have a big box full I should put up for
sale in my porch sale.

However, the capacitor input (C-L-etc) filter versions such as the CORCOM's
I cite and use may attenuate significantly ("signal suck") compared to the
inductor-input (L-C-etc ) of the commercial X-10 filters unless they are
isolated by an inductor in a cascade of filters as in my case.

... Marc
Marc_F_Hult
www.ECOntrol.org

On Tue, 02 Oct 2007 04:12:28 GMT, "Jeff Volp" <JeffVolp@xxxxxxx> wrote in
message  <MyjMi.163139$ax1.94584@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>:

>Several X10 filters are bandstop, including the little Leviton 6287.  You
>can make a pretty efficient 120KHz trap with a small inductor and
capacitor.
>However, a low-pass needs much larger components to have the same
>attenuation at 120KHz.  The Leviton 6288 and XPPF are low-pass with an
>initial break at 13Khz.  As you know, they are rated 5A, but run warm (and
>stink) when pushed that hard.  FYI, the AF120 schematic I have shows the
>inductors are 7.2uH, and all caps are 0.22uF.  The fuse may be needed for
UL
>approval if the center cap is not rated for across-line applications.
>Interestingly, the center cap on the little 6287 is listed as 1.0uF.
>
>Since these filters were designed as companions for X10 modules, they
>probably take advantage of the bandpass characteristics of the modules
>themselves.  The module's input network will attenuate out-of-band
signals,
>so the in-line filters only have to block in-band noise.
>
>Jeff
>
>"Marc_F_Hult" <MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote in message
>news:4243g31r2rvv6mg43a5g3uli7lji7jsrid@xxxxxxxxxx
>>
>>I recently added what I thought were going to be "X-10 filters" to the
>> relay controlled air-gap disconnect and filter unit that I use to
protect
>> and isolate (i.e., "filter") X-10 and INSTEON ~120khz signals from the
AC
>> circuit used for audio and instrumentation.
>>
>> These are X-10 PR brand , model " XPF 20-amp Wired in-Filter " with a
>> documentation sheet dated 10/98.
>>
>> To my surprise, they are  band-stop, rather than low-pass, filters.
>>
>> The low-pass part of the design is  L-C-L-C-L with 7.7 uH ferrite stick
>> inductors (measured at 1 kHz) in series and 1.0uF capacitors to neutral.
>> But the three inductors are each bypassed with 0.22uF capacitors. My
need
>> and intention is to filter high frequencies from the power line so I
>> removed them.
>>
>> Interestingly, ACT's popular AF120 filter uses an L-C-L configuration
with
>> 8.0 ufd toroidal inductors, 2.2uF cap that presumably has a lower cutoff
>> frequency and lower slope. It also has 0.22uf  bypass caps on each
>> inductor. There is a 1-amp fast-blow AGC fuse in series with the 2.2uF
>> capacitor's signal path to neutral. The AF120 is marked as "No User
>> Serviceable Parts Inside  Tampering Voids Warranty" on the sticker/label
>> that serves to seal the case. So if the internal fuse were to blow,
>> filtering performance would suffer but the user would have no indication
>> of
>> decreased attenuation. (The AF120 also has a user-accessible 15amp fuse
in
>> series with the load but that's not what I am referring to.)
>>
>> I haven't done a SPICE model or other calculation of these devices/
>> schematics in part because I haven't located  the reference that I had
on
>> measured/estimated typical impedances of household AC networks/circuits.
>>
>> My question is why are these filters bandstop and not lowpass? Is this
for
>> circuit protection as implied by AF120's internal fuse. Or to purposely
>> transmit X-10 across the filters? Or ?
>>
>> ... Marc
>> Marc_F_Hult
>> www.ECOntrol.org
>


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