Author Topic: Dummy Load for LED lights / eliminate flickering  (Read 215499 times)

Offline autotoronto

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #30 on: February 03, 2012, 10:59:48 am »
Quote
I also wonder what the difference is between using a 1650 ohm shunt for each fixture in a specific 3-way circuit compared to using a 40 watt incandescent bulb as a "shunt"?
It occurs to me that incandescent bulbs are much more non-linear than resistors. The filament has a higher reistance when hot than cold. This might work to the advantage: you might be able to use a lower wattage of bulb to ballast a dimmer than a straight resistor. The balast current is needed most when the load is off, at which point a bulb in shunt would remain cold, and low resistance. When the load is running at high level the bulb filament heats and its resistance rises.

So it might be that if you need a 10W ballast load, a 5W bulb might do the same trick.

On the other hand low wattage bulbs have narrow and fragile filaments.

Anyone want to experiment further?

Offline silvereagle2208

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Quck and Dirt Test -- Dummy Load for LED lights / eliminate flickering
« Reply #31 on: February 04, 2012, 12:58:35 pm »
Yesterday, I tested two dummy loads on a Leviton 600 W dimmer, no neutral,  3-way circuit to see if I could eliminate flicker: one load worked the other did not.  My test environment was a Leviton VRI06 600W dimmer in a 3-way configuration.  The only lamp in the circuit is a ZetaLux Pro 2 LED lamp.  I tested using two lamps as shunts: a 7.5 watt night-light bulb and an 11 watt signage bulb.   The 7.5 watt bulb gave marginal performance.  The 11 watt lamp appears to give rock solid performance.   It should be noted that I am not trying to see how well the circuit functions as a dimmer.  What is more useful to me is to take my energy cost for the circuit from 60 w to 18 w.

I now have another issue to deal with.  The circuit in question is the lamp is the lamp circuit for a ceiling fan.   In normal operation the LED lamp would be enclosed in a glass globe.  I have seen numerous warnings telling me to never use an LED lamp in an enclosed fixture because it will be very detrimental to the life of the LED lamp.  I might be able to take a chance with a 7 watt LED lamp inside the glass globe of a ceiling fan fixture.  However, the 11 watt "shunt" lamp that I would need to make the circuit function greatly increases the stakes.  Even though shunt lamp is only 11 watts, it is still too hot to handle with bare hands during normal operation.  I am afraid that if I place the two bulbs in the same globe, I will soon have a "fried" LED lamp after a relatively short period of time.

So I am now looking at two options: try to find a vented ceiling fan vented glass glove - no luck to far or to use a shunt resistor similar to one described in this thread and mount it somewhere on the ceiling lamp fixture somewhere outside of the glass globe.  I anyone has any suggestions regarding what I can do in this situation, I would appreciate hearing from you.

At any rate, I now know that if you have a  no neutral, two traveler wire, non-dimming,  3-way circuit and you want to replace an incandescent lamp with an ZetaLux 2 Pro LED lamp in an open, well-ventilated fixture, using an 11 watt signage bulb as a shunt might work.   However, just remember that this is not a recommendation, it is merely an observation.  You assume all risks for doing this in your own environment.

Offline TimAlls

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #32 on: February 06, 2012, 12:45:57 pm »
@silvereagle2208
Some of the LED bulbs generate quite a bit a heat so enclosing them would be bad......perhaps you could create a couple of air vents above the glass dome to give it a place for the heat to go....that is going to be a tough one!
In regards to the dummy load....I am going with 1K resistors because the dimming was smoother with a 10 Watt load. The resistor could be mounted on the metal housing to the fan....if mounted to a metal structure the heat spreads out nicely and is disipated into the air......it's not much heat but enough to be cautious with. Keep us posted as to the outcome. I have fans with three lights on the bottom and the LED's would work fine with that arrangement....I am unsure if you could change to that configuration. Good Luck.

@autotoronto
I would be interested in any testing you do with your dimmers.....the goal here is to use the smallest amount of energy and create a functioning LED lighting circuit. For me, 10 watts of wasted power to correct for the reactive loading which screws up the dimmer circuits. Of course we saved when we switched to LED's but it is a shame to loose the 10 watts to create a functioning dimmer!
Regards
Tim Alls
AllSeas Yachts
« Last Edit: February 06, 2012, 12:47:31 pm by TimAlls »

Offline TimAlls

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #33 on: February 07, 2012, 10:55:28 am »
My resistors came in yesterday......here is how I am curing the LED flickering issue on ten different dimmers. Remote mounted dummy loads, 1K or about 10 watts added to the output of Leviton 1000W Dimmers.
More to come.
Regards
Tim Alls
AllSeas Yachts

Offline autotoronto

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #34 on: February 07, 2012, 01:47:53 pm »
Nice install. Can I suggest a dab of heatsink paste under each resistor, if you didn't already use it?

Offline TimAlls

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #35 on: February 07, 2012, 01:56:33 pm »
Nice install. Can I suggest a dab of heatsink paste under each resistor, if you didn't already use it?
You are right on target! Yes we will as well as adding fins to the back side of the panel.  ..........EDIT.....there is no heat build up so no fins are needed.
I will be checking the temp with our laser.....going to run them all 24 hours at full intensity then check the heat build up.
More to Come....
Regards
Tim Alls
« Last Edit: February 07, 2012, 07:41:02 pm by TimAlls »

Offline TimAlls

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #36 on: February 07, 2012, 07:39:02 pm »
Here is the final install....we have been running full power for hours and the heat build up is just warm to touch....that is with 10 circuits running all at once.
I will check it's temperature tomorrow but It appears that the LED dummy loads are going to work fine!
We took the output of each dimmer and fed them into the resistors shown....the common white ties them all to neutral.
The light CANs are next but I see no problems.
Regards
Tim

Offline TimAlls

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #37 on: February 08, 2012, 11:19:18 am »
Hi All,
Final heat testing this morning after running all 10 circuits all night.....backing plate is at 89 degrees......same as yesterday, just warm to touch.
Bugs:
LED's don't ramp up like the normal bulbs
Dimming is not perfectly smooth to the eye but the dummy load makes dimming linear
LED's can't go below 10%

On the upside is lower energy, and no changing of the lightbulbs!

Regards
Tim Alls
AllSeas Yachts

Offline pgrover516

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #38 on: February 08, 2012, 02:16:47 pm »
great stuff, Thanks again Tim
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Offline tinkerdoctor

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #39 on: February 12, 2012, 06:22:58 pm »
Inductor wouldn't work, but what about capacitor, it should? 

Offline TimAlls

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #40 on: February 13, 2012, 04:28:08 pm »
Inductor wouldn't work, but what about capacitor, it should?
A Capacitor will react with circuit similar to an inductor since it runs on AC.....The resistors are non reactive and seem to work fine!
Regards
Tim Alls

Offline tinkerdoctor

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #41 on: February 13, 2012, 06:27:58 pm »
Inductor tend to keep the current flowing when the circuit is turn off and cause large voltage spike when the circuit is turn offr which damage the switch (arcing on dry switch and short on semiconductors).  Capacitor keep the voltage the same which actually protects the switch.  I did some calculations and came out with 35micro F as equivalent to 5W bulb.  To be safe you need 600V peak.  At Digikey they cost about $15. It will take about 15 years to recover the cost of electricity saved but it also avoid the issue of local heating.

Offline pgrover516

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #42 on: February 13, 2012, 07:24:49 pm »
Inductor tend to keep the current flowing when the circuit is turn off and cause large voltage spike when the circuit is turn offr which damage the switch (arcing on dry switch and short on semiconductors).  Capacitor keep the voltage the same which actually protects the switch.  I did some calculations and came out with 35micro F as equivalent to 5W bulb.  To be safe you need 600V peak.  At Digikey they cost about $15. It will take about 15 years to recover the cost of electricity saved but it also avoid the issue of local heating.
between the electronics and the led bulbs i may not live long enough to see the savings, lol   :P
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Offline TimAlls

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #43 on: February 13, 2012, 07:50:53 pm »
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between the electronics and the led bulbs i may not live long enough to see the savings, lol   :P
On our yachts we are switching from 40 watt halogen bulbs (in 4 inch cans) to an LED replacement from the Home Depot.....$10.00 per LED bulb. The halogens ran $5.00 per bulb and we have been spending way too much time changing bulbs! A typical room has 10 bulbs so the return is very quick and even quicker if your labor to go get bulbs and change them is taken in to consideration! ;D
It doesn't take a lifetime to pay for the LED's .... but it is a bit of trouble to add the dummy loads.
No one is calculating the reduction in HVAC as well....that is the biggest saver.
Regards
Tim Alls
AllSeas Yachts

P.S. the temperature of a 1K resistor is 170 degrees.....the surrounding heatsink in my photo never gets above 85 degrees even after running days at full power.

Offline pgrover516

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Re: Dummy Load for LED lights / eliminate flickering
« Reply #44 on: February 13, 2012, 11:27:08 pm »
Thanks again for your solid R&D, despite my jest I'm excited to begin conversion to led at the house this weekend. Cheers!
Paul
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