Re: I think they've done it again.

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Sun, 25 Jun 2006 12:00:22 -0400, Marc F Hult
<MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote in message
<1f7t92ll7oa28ospsqhfbm3bdvmhqe5nco@xxxxxxx>:

>
>Mike from INSTEON wrote in
>http://www.techmall.com/post.asp?method=ReplyQuote&REPLY_ID=636&TOPIC_ID=180&FORUM_ID=9
>
>	"The component that is in question is the choke coil. Repeated
>	INSTEON signals generated by the dimmer or controller were getting
>	 into the triac and causing the flicker. We have increased the value
>	 of the choke coil to attenuate the INSTEON signals that go into the
>	 triac. "
>
>
>There are two inductors in an ICON dimmer with an MCU marked "GL2476D BETA"
>with stick-on label. They look just like those on the other model INSTEON
>dimmers I have.
>
>The large inductor (choke) is in series with the red AC _input_ lead and
>consists in 4 turns of 14AWG on a ~15 mm diameter green toroid and has an
>inductance of ~18 uH (measured at 120 hz and 1000hz with an EXTECH LCR
>meter). The other terminal of the inductor is connected directly to the
>input of the TRIAC.
>
>In contrast, the choke on an X10 WS467 is about 45 turns of ~16 AWG on a
>25mm long ferrite rod and measures  44 uH. This construction, size and
>inductance is typical of residential dimmers.
>
>"Specification grade" (architectural grade) dimmers have much larger
>inductors. This is one of the inherent advantages of centralized dimmers
>over wall-mounted dimmers because there is no practical limit to the size of
>the inductors in a centralized dimming panel.
>
>(The ICON dimmer also has another, low-current inductor in series with a
>diode near the coupling transformer.)
>
>If, as it appears, the problem is with the high-current input choke and can
>be solved by doubling the inductance, more turns on the inductor would do
>the trick if that doesn't cause the inductor to saturate. But if a
>physically larger inductor is needed, space will be a problem. The INSTEON
>dimmer cases are/can be made shallower than most other dimmers in part
>because the choke is smaller.

As I understand it, a field fix that has been considered by SmartHome is to
wrap the load wire several times through a external toroid choke core. In
other words, add more inductance in series to the (measly) ~18uH provided by
the T-16 toroid choke (labeled L3) they already have in the dimmers.

That's easy enough to do if you have enough volume in the switch box and is a
conventional fix for filament buzz and other noise-induced problems.
Commercial de-buzzer coils  I am aware of are typically need an additional or
very large switch box.

... Marc
Marc_F_Hult
www.ECOntrol.org