New 12v LED Fixture with Existing Panelized Lighting

[Jeremy Ragan]

Hello, I will be replacing an existing ceiling fixture with a new one but my project has a number of complications.

Old Fixture:

• 12-volt track-style fixture
• 12-volt WAC Lighting remote transformer SRT-300M-12V

New Fixture:

• 24-volt Nemo Ellisse Double LED Suspension Light
• Uses integrated transformer LPF-90D-24
• Apparently, for dimming, the fixture/transformer requires an additional 2 wires be run from the dimmer according to some things I've read

Power Source:

• Lutron Homeworks Interactive (circa 2004) Panelized lighting RPM/Dimmer

Questions

• Confirming that I will be bypassing/removing the existing WAC Lighting transformer...
• Will this fixture dim without running the extra 2 wires?
• Will the new fixture work/dim with the existing feed from the panelized lighting?
• If wires must be run for dimming, then where would they run from?

When I tried to clarify with the manufacturer, I received the following:

ELLISSE PENDANT DOUBLE is

• 24V
• Dimmable 1-10V (you need 2 wires)
• The driver inside the canopy is already dimmable: you need only a 1-10V controller

But this doesn't seem to clear up my confusion. 14-2 is already run to the existing transformer and then more 14-2 from the transformer to the existing fixture. Are they saying I need 2 more conductors in addition to the 2 in the ROMEX?

Thanks, Jeremy

 

[Jadnashua]

The unit does require a compatible dimmer. The unit appears to support acv input constantly, and you can then control the light output via the dimmer. Or, you could use a simple on/off switch, with a separate, compatible dimmer. The power and dimming are on two different cables. The dimming signal doesn't need 14g wire, something smaller would work since it has no current.

The output of the dimmer is NOT acv, it is one of three things:
- an adjustable 0-10vdc level where 1vdc=10% brightness
- a variable resistor from open (full on), to about 10Kohms for each 10% (so a 10Kohm resistance would produce 10% brightness, and a 100Kohms would produce 100% - an open would be the same as full on)
- a pulse width modulated signal in the acceptable range (300Hz to 1KHz), where 10% duty cycle produces 10% brightness.

I have no idea who makes a compatible dimmer.

https://www.mouser.com/ds/2/260/LPF-90D-spec_5-1109537.pdf

 

[Sponsor]

 

[WorthFlorida]

As soon as I open the URL link I could tell it's an European company. The technical data reads "tension" instead of "volts"was another clue. The dimmer is something different with a step voltage control and none of its pages mention any dimmer models offered. Another item is the energy sheet, it is dated 2012. LED offerings and dimmer controls has come a long way since 2012. It's a real nice looking LED lamp but unless you can find a US supplier that sells all of the components for it, I would look for something else.

NEMO USA
625 Jersey Avenue,
Unit 7
New Brunswick, NJ 08901

 

[Jadnashua]

All you need is a rheostat (variable resistor) valued at 100kohms max. It does not need any voltage applied to it. The thing would have three contacts, but you'd only need two of them...one end, and the wiper arm. As you move the knob (connected to the wiper arm), it would vary the resistance across it from a short to 100K, which would adjust the brightness of the lamp as powered by it's own control circuit/power supply.

The other 2 acceptable controls would require an active electrical circuit:
- a 0-10vdc power supply, or
- a 10v max PWM signal generator that can be adjusted for varying duty cycles that will be interpreted by the power supply to adjust the brightness.

The resistor wouldn't make any potential electrical noise or need power to run it.

None of those control methods are part of a traditional dimmer switch generally sold in the USA. Many of the newest LED fixtures can use a suitable dimmer wall switch...this one is NOT standard, and requires its own separate control. If you can't get one from them, you'll have to cobble your own up, and a variable resistor is the easiest way to do it. The total resistance of the thing could be more than 100K, and if it weren't the full 100K (they often have a tolerance of as much as 20% unless you spend more), you wouldn't be able to get it to provide the full range to full brightness. You can get a variable resistor as a sliding control as pictured, or a rotating knob/shaft. If you were handy, you could probably figure out a way to put one in the box where the on/off switch was. Note, it appears that you can get the full 0-100% brightness with just the rheostat, but the power supply to the lamp would then always still be on...an on/off switch may be useful to make it a bit more efficient in standby.

 

[Cacher_Chick]

0-10 v dimmers are commonly used in LED lighting. You would need to wire one in separately from your existing installation.

 

[Jadnashua]

The lamp comes with its own, 120vac power supply. The dimmer circuit goes into it as a separate control. That input does NOT power the lamp, it only adjusts the included power supply output, and it can be controlled in three different ways: DC, resistance, or a PWM signal, all of which are low-voltage control signals, not power. The incoming power is NOT adjusted - it remains constant, and the input signal lines are adjusted to provide the dimming.

If you never wanted to dim them, you could just use a simple on/off switch. This is not how a typical US light fixture works.

 

[Highlander]

0-10V dimming technology was originally developped for fluorescent dimming, often in commercial settings and with 0-10V compatible ballasts. There are dimmers available for this (see example at link, they also make them to match Decora devices), no need to McGuyver stuff. One important concept to keep in mind, you run full power to the fixture’s ballast or power supply, then run a “control pair” to the dimmer, same way we often wire in a “switch loop”. Not sure how you could integrate this with a “panelized” dimming system, tho.

https://www.leviton.com/en/products/ip710-lfz

 

[Jadnashua]

Thanks for posting that Highlander...learn something new every day.