ok so I am wiring under / over cabinet lights for a customer. previous under cab lights have a Lutron
AC dimmer feeding to a magnetic 12v 40 watt max transformer wired to the led strings. worked fine when I pulled down the cabs. and I did have to disconnect the dimmer switch.
now...attempting to reconnect and the switch sends power to the transformer but the feeds for the lights only register .7-.9 watts. another transformer registers .03. no lights working...no difference in voltage when I adjust the dimmer...
when I first tried the switch there was a very faint flash on a new string, then nothing...tried different strings....nothing...
LED's are a strange bunch. LED's require a transformer for proper power control. The lutron dimmer should just be a standard voltage modifier and if you replace it with a traditional switch, the LED's should come on at full brightness. LED's do not need much power but .7 to .9 seems like the LED's would be fully dimmed. .7 to .9 amps would be more in line with expectations.
You removed the dimmer connected to transformer connected to LED string. You put it back but the LED's won't light. Was anything else connected to the string like an extension? The flash you describe makes it seems like the transformers electronics do not like the input voltage they are receiving.
We had a lot of old lights at the new home and they simply would not run LEDs - had to get new fixtures. Worked fine with regular bulbs - it was strange. Most had like 3 bulb outlets that worked with reg bulbs and one that didn't work with either. With LEDs only one would work.
i don't understand why the black 110 wire is hot at the transformer but the transformer output does not fluctuate when I adjust the dimmer...maybe a bad ground?
Only think I can think of is to test each part separately. Does the dimmer dim incandescents? Does the transformer put out the right voltage on 120v power? etc.
Only think I can think of is to test each part separately. Does the dimmer dim incandescents? Does the transformer put out the right voltage on 120v power? etc.
LED's require a transformer because they can't accept 110V. LED's are 3.2 to 3.6V nominal. Transformers have to step the voltage down otherwise the LED's would just pop.
LED's require a transformer because they can't accept 110V. LED's are 3.2 to 3.6V nominal. Transformers have to step the voltage down otherwise the LED's would just pop.
Agreed. No LED's straight to 120v. That's bad. ...but with another power supply (old wall wart) it would be good to make sure nothing popped in the LED strip.
can you just remove the dimmer and test it? dimmers are weak sauce as far as useful lives - - they also are a PITA to LED bulbs that aren't ready for them.
can you just remove the dimmer and test it? dimmers are weak sauce as far as useful lives - - they also are a PITA to LED bulbs that aren't ready for them.
He says it was working fine previously. If that's the case, then relocating LED's and dimmer to a new location shouldn't affect their operation. Dimmers have a higher than average failure rate but LED transformers have an even higher failure rate than that. Look at all the LED street lights that rapidly blink or are running dim. Those are all failed transformers. LED's by themselves are very robust and hardly ever fail. They can get too hot which will shorten their life considerably.
