Re: X10 signals can be TOO strong!

["Alan Vogel" <avogel2@xxxxxxxxxxxxx>]

It looks like the 30Vpp signals that appear on the MT1 and MT2 pins of the
triac are exceeding the triac's dV/dt spec.  These signals capacitively
couple to the triac's gate and turn it on.  Sensitive gate triacs typically
have higher dV/dt limits, but are probably not used in the modules because
they are more expensive.

Alan

"Jeff Volp" <JeffVolp@xxxxxxx> wrote in message
news:xFhfh.471684$QZ1.157389@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> The tree went up yesterday, and it was put on a lamp module set to the
> same
> codes as our other Christmas decorations, which normally run about ½
> intensity.  The tree exhibits the same flickering effect reported earlier
> with some Insteon wall switches.
>
> Some background:  The family room receptacles are all on the same circuit.
> The Ocelot interfaces to the powerline through a XTB-II, which is also in
> the family room at this time for convenient testing.  We have not seen
> this
> effect with two other lamp modules on that same circuit
>
> The inductance in the run down to the distribution panel reduces the load
> on
> the XTB-II, allowing the signal in the family room to be almost 30Vpp.
> When
> coupled into our distribution panel, the heavier load reduces the XTB-II
> output to about 20Vpp, but that falls off as the signals propagate away
> from
> the distribution panel.
>
> Apparently a 30Vpp X10 burst is sufficient to couple into the lamp
> module's
> triac, causing it to trigger full-on for those half cycles of the AC
> power.
> This causes flicker in sync with each X10 transmission.  Actually, it's
> kind
> of neat because I can see whenever the Ocelot is sending out a command.
> The
> effect was most evident last night as the module was stepped down to max
> dim.
>
> All three lamp modules exhibit the same characteristic with that heavy
> load.
> None of the modules flicker at all with a dimmed 75W table-lamp load, even
> at the same receptacle.  The lamp modules are from various eras.
>
> I thought I would share this observation in case anyone else experiences
> something similar.
>
> Jeff
>
>