T67 and T91/ Glimpse LED Lights Dimmer Video

This week I received twelve T91 LED lights, found in listing at ebay. At a price of $24.95 each and with free shipping, I was willing to take a chance on these "surplus" lights, not in original packaging, origin not explained. The ebay listing by New Life Electronics is regularly renewed, with seemingly an unlimited supply. In the box there were six of the original  T91/ Glimpse design, and six of the current, improved design.

With these lights, and with six T67s in addition, I am able to expand understanding of how LED disk/ plate lights behave when operated on a dimmer.

Here is a video of the operation of sixteen LED disk lights in parallel, controlled by one Cooper Wiring Devices D106P dimmer, Sixteen In Parallel.MP4  

Here is a back-side comparison of original and current T91/ 6" Glimpse lights:

Here are some conclusions from this testing:

• The number of lights that may be operated from one dimmer is limited by the wattage rating of the dimmer. A 600 watt dimmer can operate forty 15 watt luminaires, carrying five amps.
• The original T91/ Glimpse with two clunky power blocks is unacceptable on a dimmer, if there is more than one light. If you buy via the ebay link and intend to dim, demand newer version in communication with the seller. I think I got as many of the older version, as the seller thought I might tolerate.
• One of the six older T91s failed in minutes of testing, never to fire again. This is the second failure of this kind I have seen. This is another reason to refuse buying the older version. I doubt I have recourse now, with the seller. I will want to break apart and examine one of the failed lights. I wish failures and fixes were freely discussed by manufacturers and their major distributors.
• I had claimed the newer T91/ Glimpse has been cured of humming in a dimmer circuit. Not so! I have just never been able to hear the hum from any distance.
• Seven T67s I have tested now on dimmers, have identical and objectionable hum, in  a dimmer circuit. It isn't a simple problem. LSGC did not in fact find a cure for Glimpse. Some smart person could figure out why the Glimpse lights make less noise. It may be a subtlety of mounting provisions and structure natural frequencies, vs. the AC power at 60 Hz.

I suggest there has been only one change of the 6" Glimpse/ T91 design. Please see my post, where I comment on visible differences. I call the two versions 6A and 6B.