LED strobing. Neutral interaction on a residential project?

[RDean]

Good morning.


This is my first thread. I could use some guidance please.

I have a project which of course is an hour away and has developed a significant problem. Our firm supplied LED lighting for a family room which is part of a much larger residential remodel. It consists of 8 mono-points with plug-in (phono-jack style) track heads that are lamped with Soraa MR16s. The driver spec sheet for the mono-points state, they recommend reverse phase dimmers. It is also recommended to be used with AC LED and Halogen loads so, I suppose it's not a driver in the strictest sense of the word.

Dimming was supplied by another vendor who is local to the job. The dimming devices are manufactured by Savant of which I have no history with. I understand that the devices are universal and auto sense the type of load then, adjust to forward or reverse phase control as needed. In this particular case the device defaulted to forward phase, but has been manually set to reverse phase since it was commissioned.

The symptoms we're having are as follows. Initially one of the mono-points hard failed. Two others failed by strobing in unison. This goes back to almost 2 months ago. I have supplied 3 replacement drivers for the ailing units, but suspected there was an external cause for the failures. Service is scheduled for today but; yesterday the customer informs us that now they have 3 that hard failed and, the remaining 5 strobe in unison.

If this was a commercial application I would say this would likely be a shared neutral problem. I've seen problems like this many times before. All were in residential settings. Some localized with one or two switch legs or, the whole home. I would also add we have other locations in the home, dimmed and non-dimmed, have the same product, and don't exhibit any symptoms.

The hard failures are a first. I almost NEVER have drivers or transformers die on me and, the fact that I have 3 on the same switch-leg, along with the strobing in unison is highly suspect. I'm reaching for straws here, but would it make any sense to switch the breaker from the A phase to B or, vice a versa?

Please chime in with ideas. I don't know where to start. Savant's tech support is highly guarded and my lighting vendor, Tech Lighting has limited resources beyond their own product.

Best regards,
Roberto

 

[PaulMmn]

You said the dimming was supplied by another vendor. Is the dimming compatible with the drivers and the lamps?

 

[synchro]

Perhaps the driver at the mono-points is what's sometimes called an electronic transformer.
This is a guess, but if this driver has a ground connection (to the EGC) then its circuitry might be damaged if the hot and neutral wires were reversed. A magnetic transformer would not be affected. So it might be worthwhile to verify that there's no significant voltage from the white wire to ground wire at the driver's supply side connections.

 

[Metallicbeing]

What is the total wattage placed on a single dimmer? Some of the limitations per dimmer (depending on brand) are 250 -300W (LED) & 500W (Incandescent).

 

[Metallicbeing]

Ensure your MR16 Lamps are rated for AC Dimming. Some LED MR16's use Electrolytic Capacitors (After a Bridge Rectifier) to help smooth out the lighting brightness.

 

[Metallicbeing]

Better check that you're operating at the correct voltage. It's very suspicious that some of your fixture transformers/ power supplies died on startup. I believe most modern power supplies are required to have a short dropout circuit on their outputs. This can also manifest as flashing.

 

[Electricmo]

I would suspect the dimmer switch isn’t comparable with the lights if there is no other voltage issues in house.