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Industrial LED lighting on a dimmer 3

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watermarkhe

watermarkhe

Electrical
Aug 13, 2024
1
A friend replaced his fluorescent tubes with direct wire LED tubes, 80 of them. At 14W each, that came to around 1200W. He wanted a dimmer on it, but it was only rated for 300W and obviously got hot. I was helping him look for a higher rated dimmer but not having any luck. The 40W fl's were on 2 circuit breakers, 3.2kw, so he tied the LEDs together into one of the breakers and disconnected the other. I'm assuming the limited wattage for a wall dimmer is due to physical size...is there a way to safely install a dimmer for 80 14W led tubes or is there such a thing as a 1200W LED dimmer?
 
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There are electricians who know what they are doing...

When one this sentence into the German to translate wanted, would one the fact exploit, that the word order and the punctuation already with the German conventions agree.

-- Douglas Hofstadter, Jan 1982
 
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Not all LED lamps are suitable to be connected to a dimmer. I'd say most aren't, to the extent that you should assume it cannot unless it explicitly says that you can. Obviously the rest of us have no knowledge of exactly what was installed.

Reason: the device has an internal regulated power supply that tries to maintain constant output to the LED despite disruption of the input voltage, unless specially designed.

From my poking around hardware stores looking for bulbs, at least around here, household screw-in bulbs (incandescent replacement) are somewhat likely to be dimmer-compatible because of the number of household fixtures that are on dimmer switches, and fluorescents never (that I've seen) have dimmer switches so there's ordinarily no reason for an LED replacement to be expected to be put on a circuit with a dimmer switch.
 
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The dimmers for fluorescent lights usually involve specially designed dimming ballasts, having a dimming control connection. This is usually a o to 10 volt connection.
LED Lighting ballasts are available with a o to 10 Volt dimming control connection.
So if your ballasts have a control connection, you can probably drive it (them) with a 0 to 10 volt power supply (lighting controller) (Check the ballast data sheet). If your ballasts do not have a control connection, you likely can't dim them, as most LED (and fluorescent) Ballasts are constant power for a wide input voltage range. Attempting to dim by lowering the supply voltage will increase the source current demand.

There are some other designs, used for dim-able LED systems, the documentation will state if they are dim-able, and what additional components are needed.

Residential A10 (Edison screw base) form LED's that are dim-able are designed to use the supply voltage as the ballast control signal.
 
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Are rheostat dimmers still used in residential lighting? I thought they were all chopper/triac dimmers by now.
 
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Even a chopper dimmer that doesn't get hot during normal operation within its ratings, is probably going to get hot when used to handle 4 times as much lighting load as it's supposed to!

The system described in FacEngrPE's link looks like the right way to do this. You'll have to investigate whether the LEDs that were installed are compatible.
 
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Chopper dimmers simulate the reduced voltage of a rheostat on an incandescent light bulb. The thermal inertia of the filament will with a 50 Hz or 60 Hz power supply smooth the flicker to tolerable levels. At 25 Hz or 15 2/3 Hz flicker can be noticeable.
To get flicker free lighting with LED's the ballast needs some filtering.
[URL unfurl="true" said:
https://youtu.be/3Oninyogwtg[/URL]]Inside a Sainsbury's dimmable LED bulb
bigclivedotcom
Aug 23, 2024 #ElectronicsCreators
The circuitry in dimmable LED bulbs is much more complex than non dimmable ones, because they have to interpret the chopped up sinewave as an intensity.
The modern bulbs like this one do it by using a current regulator to charge the main capacitor, so that the duty cycle of the sinewave affects the voltage the capacitor charges to.
In this case, an extra auto adjusting component has been added that then scales the LED current down to match the reduced charging of the main capacitor by detecting excessive ripple current.
I'm not sure what the chip in this circuit actually is. It has a code that suggests it is batch marked for a bulb manufacturer.

If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty.
Click to expand...
 
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All this talk of dimming ballasts, rheostats, choppers, etc. are off topic. OP's friend bypassed the florescent ballasts to direct wire LED tubes that have the drivers as part of the lamp, and now wants dimming capability. See BrianPetersen's first response above. Rather than junking 80 new tubes, I would propose dividing the circuits up so groups of tubes could be switched independently. Might even be able to find radio controllable switches that would minimalize the amount of re-wiring involved.
 
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