Hello
I am new to this forum and am hoping to find some help. We need to have dimmers that can control 1000-1500 watts (actual watts not LED equivalent) of led lighting. We have light strands that we put in structures that have a bulb every foot that use 1 watt per bulb. These strands are about 100feet long and we put many of the strands together on a splitter that goes to a dimmer switch. These switches are 300-500 dollars each and I am wondering if I can make them my self at a significant cost savings. The light strands run at 120 volt. I saw some instructional videos on you tube but they are not meant to control this high a wattage. I was wondering what people think on this idea.
thanks

 

Welcome to AAC!

If the user of these requires, or should have, UL approval, it'll be less expensive for you to buy them.

 

Thank you dl324. I guess even with that being said I would still like to know how to make something like this myself.

 

I would still like to know how to make something like this myself.

First search hit:
What is a Triac Dimmer? Everything You Need to Know (electrouniversity.com)

EDIT: I've seen the cost of getting UL approval to be $5-50k. Don't know what the fee is to keep it current.

 

First things first.
Do the LED drivers you are employing support dimming? That is the absolutely first thing you require to investigate

Triac dimmers are fairly straightforward and a 1500 watt is really not much for thyristors.

 

Certainly high wattage dimming can be done, and the designs are not new, although the newer hardware may be more efficient.
The very first thing is to verify what kind of dimmer scheme that is already in use, because I have discovered that not all dimmer schemes work, even when the label clearly states that they do work.
Then you will need to know how much current you will be controlling at the maximum brightness. That will determine the current rating of the SCRs or triac devices that you select. So verifying that the LED devices you are using is vital.

There are all different kinds of dimer schemes including at least one using a counter

Also you will need to decide on the control adjustment method.

 

Just a word of caution on “dimmable”. There is no official standard or definition for what is necessary for an LED luminaire to be sold as “dimmable”.
I suspect it means that it was tested on whatever dimmer the luminaire manufacturer had to hand. It doesn’t necessarily mean that it would work on any other dimmer.

 

I have a client who purchased "dimmable" fixtures. The first dimmer I tried produced a strobe-light effect, the second dimer, claiming on the package to be able to dim all LED lights, produces no effect at all, It seems that these fixtures include a constant current ballast. So it may take a greater change.

 

These are E17 led dimmable bulbs, 120v. I cannot control these on the low voltage side. I have used led dimmer switches like the ones you would get at your local big box store and they dim well with those switches. The problem is that these switches are limited in the wattage they can handle.
thanks

 

I came across a circuit that certainly can be scaled up to at least the kilowatt level, in an old publication, "The GE Electronic Components Hobby Manual", Second edition, 1965. It shows a circuit for using phase control to vary the firing angel of a triac. Certainly a similar scheme could control a current technology triac able to handle a lot more current. There is another circuit, a bit more complex, that uses a pair of transistors controlling a unijunction transistor driving a pulse transformer to trigger a triac. That circuit offers the benefit of the control being an isolated DC voltage.
While both circuits use lower power devices, the same scheme can control devices able to handle much greater power levels.