"Smart" Dimmers and one side effect?

[timhoward]

Of late I've been using smart dimmers. And they do the job very well.
In a couple of cases turning another light on in the middle of the circuit cause the dimmer-controlled lights to briefly go out and then light again. I'm guessing the dimmers are adapting to the change in circuit resistance.
Is this a scenario anyone else has had and are there any solutions that don't involve re-wires?! Or is one of those things you have to live with.
Thanks for any comments.

 

[SJD]

The 'other light' that causes the brief drop-out, I'm assuming this is LED, perhaps with a high inrush current as it starts? Some dimmers have a soft start, so wondering if this 'other light' is put on a soft start dimmer, does that reduce or eliminate the effect?

 

[timhoward]

The 'other light' that causes the brief drop-out, I'm assuming this is LED, perhaps with a high inrush current as it starts? Some dimmers have a soft start, so wondering if this 'other light' is put on a soft start dimmer, does that reduce or eliminate the effect?

Thanks, I like the thinking. I'm going back sometime soon for a different job and my intention was to note the exact fittings and bulbs and acquire exactly the same setup for experimenting with. I had also wondered about a capacitor in parallel as found in fluorescent fittings.

 

[Lucien Nunes]

Possible interactions include a brown-out, i.e. momentary drop in voltage due to the inrush of the incoming lamp, and interference, i.e. noise or spike(s) generated that don't involve a significant drop in voltage. From the point of view of the dimmer that blinks off, it might not be the actual low voltage that is the issue but what it perceives as waveform distortion disrupting its timing generator that controls the firing phase angle, causing it not to fire or to reset.

If the dimmer interaction is caused by line-borne HF noise or transients then a parallel capacitor might help by bypassing them. If it is caused by waveform distortion or low average voltage due to inrush, it won't really make any difference as its reactance will be orders of magnitude higher than the circuit loop impedance.

The parallel capacitor in a conventional fluorescent fitting is to correct the displacement power factor of the lamp current, which lags the voltage due to the ballast. The non-linear nature of the lamp conduction also heavily distorts the current waveform, but most of the important harmonics are still at frequencies where the capacitive reactance is mugh higher than the loop impedance, so these return to the supply rather than being bypassed by the capacitor.

 

[static zap]

Possible interactions include a brown-out, i.e. momentary drop in voltage due to the inrush of the incoming lamp, and interference, i.e. noise or spike(s) generated that don't involve a significant drop in voltage.

Or Harmonic interference between brands.
Does make me skeptical they are Designed to be fussy ..
To encourage brand loyalty on the same lighting circuit ,
do we need some inter-brand tolerance specifications , for fair
competition / not creating electrical waste from used once products -
[NOW out of virgin re-sale state ! ]
Some bits are not cheap !

(Early PC SMPSUs were knocking chunks out of the mains cycle )