SNUBBER Solutions ??

[griffixdc]

i have been reading many threads and and even on planet christmas forums it seems some people have some luck with snubbers and most people dont.

The idea of a snubber is to act in opposite to a capacitor and remove extra charge in the channel or string of LED lights....it happened more so than not on LED strings with a four Diodes /(rectifier) in it ...many solutions have been posted but they help but still dont get rid of the annoying problems .

What i am thinking without any equipment to test this is to have a diode limiting current to go back to the controller, then a capacitor, then the rectifier/ or 4 diodes then the light string then the resistor at the end of each series of LEDS...this might completely get rid of all stray current on the lines that inductance or what have you has created...

just an IDEA i may be completely wrong so any feed back critical or good is appreciated :)

the next set of ideas is to put 2 resistors inside the rectifier in parallel to the diodes to. it should release any spike voltages/current on each plane of the sine wave


????dunno i could be smoking something lmao

[P. Short]

I stopped following those threads about snubbers on planetchristmas.com a long time ago. There was a solution that appeared to work for some number people, but the explanation of what caused the problem (and how the snubber solved it) was never very convincing to me. I think that it takes a deeper, more detailed understanding of the subtleties of the LED strings than the people there possessed, or anyone here for that matter. So, try it, but don't be surprised if it doesn't work or if it only works in limited circumstances. This is especially true because some of the LED string manufacturers have added extra circuitry to the LED in an attempt to reduce flicker, and these affect how the strings interact with various dimmer designs.

[dunnsr]

puff puff PASS


sorry too funny to resist... the only thing that i seen that might be worthwhile was the added load of a resistor, i was going to put them right at the board, and only if my led's flicker... i wont have more than 1 or 2 sets per channel, so it might not happen.. i just dont know until i get my dongles, and a board built.

seth

[Entropy]

I think the extra load people have often solved LED strand problems with is not really a snubber - The problem with LED strands is that they are simply a far lower load than most SSRs expect, and a fairly nonlinear one, however not one that is significantly inductive or capacity. Since they have far lower load, it is easier for line noise and transients to false-trigger the triacs. Adding some constant nice linear load solves this problem.

Snubbers are typically the solution used when a triac-based SSR needs to drive a significantly inductive or capacitive load - in these cases the circuit may be linear but have significant phased delay in the I/V curve.

[griffixdc]

I think the extra load people have often solved LED strand problems with is not really a snubber - The problem with LED strands is that they are simply a far lower load than most SSRs expect, and a fairly nonlinear one, however not one that is significantly inductive or capacity. Since they have far lower load, it is easier for line noise and transients to false-trigger the triacs. Adding some constant nice linear load solves this problem.

Snubbers are typically the solution used when a triac-based SSR needs to drive a significantly inductive or capacitive load - in these cases the circuit may be linear but have significant phased delay in the I/V curve.

so what you do you suggest creates the "load" so the triacs reconize the LED strands....if i have 1 amp of LED's on a channel isn't that enough load for the SSR to recognize?

i have watched LED light shows .....Only LED, and i didn't notice any of the problems that are common to using LED's...but of course those people are un willing to respond back or paid to have some create the display for the.

[budude]

I think the extra load people have often solved LED strand problems with is not really a snubber - The problem with LED strands is that they are simply a far lower load than most SSRs expect, and a fairly nonlinear one, however not one that is significantly inductive or capacity. Since they have far lower load, it is easier for line noise and transients to false-trigger the triacs. Adding some constant nice linear load solves this problem.

Snubbers are typically the solution used when a triac-based SSR needs to drive a significantly inductive or capacitive load - in these cases the circuit may be linear but have significant phased delay in the I/V curve.

I'm not sure I completely agree. If you read the PC thread by chuckd, you will see where he added multiple strings of LEDs and the overshoot got worse and worse with more strands. This to me supported his case that it was adding capacitance and was not due to lack of load. I'm not saying this is always the case, and I agree with Phil that perhaps some string manufacturers have taken this into account - - but you can't argue with the scope captures he provided - it clearly shows a day and night difference simply by adding the resistor. At a minimum, it certainly won't hurt to add it and it's a cheap fix if it does work.

[griffixdc]

I'm not sure I completely agree. If you read the PC thread by chuckd, you will see where he added multiple strings of LEDs and the overshoot got worse and worse with more strands. This to me supported his case that it was adding capacitance and was not due to lack of load. I'm not saying this is always the case, and I agree with Phil that perhaps some string manufacturers have taken this into account - - but you can't argue with the scope captures he provided - it clearly shows a day and night difference simply by adding the resistor. At a minimum, it certainly won't hurt to add it and it's a cheap fix if it does work.
kinda what i was getting at....
but i think if you a add a diode limiting back flow on the other channels of your controller that have leds i think this might solve all or more of this issues in combination with the resister or some voltage drain technique(ie light bulb, resistor, arch probe)

[n8huntsman]

...it was adding capacitance and was not due to lack of load. ...simply by adding the resistor.

So if I'm thinking correctly, the LED's are wired in parallel so as you add more LED's, main line resistance goes down, (capacitance up). By adding a resistor in series in the main line, you will increase resistance, capacitance down?

[budude]

So if I'm thinking correctly, the LED's are wired in parallel so as you add more LED's, main line resistance goes down, (capacitance up). By adding a resistor in series in the main line, you will increase resistance, capacitance down?

Here's the thread (http://forums.planetchristmas.com/index.php?/topic/36988-easiest-terminatorssnubbers-to-make/) if you are not familiar with it - go through it, paying attention to the scope captures and you can see the benefits.

[ErnieHorning]

All diodes have capacitance. Twisting to wires together also has capacitance. Testing showed that adding LED strings together would increase the capacitance and a string that was modified to be an extension cord and twisted, did not increase the capacitance.
Adding a resistor in parallel, is not a snubber but that's what it's being called though in this case, it has the same effect.

The added capacitance, phase shifts the current passing through the TRIAC with respect to the voltage. This seem to keep the TRIAC conducting. The resistor is the cheapest universal fix that appears to work most of the time though the success varies with the string construction.

I think the problem would go away if the output was a FET transistor instead but a TRIAC is more robust to abuse.

[griffixdc]

All diodes have capacitance. Twisting to wires together also has capacitance. Testing showed that adding LED strings together would increase the capacitance and a string that was modified to be an extension cord and twisted, did not increase the capacitance.
Adding a resistor in parallel, is not a snubber but that's what it's being called though in this case, it has the same effect.

The added capacitance, phase shifts the current passing through the TRIAC with respect to the voltage. This seem to keep the TRIAC conducting. The resistor is the cheapest universal fix that appears to work most of the time though the success varies with the string construction.

I think the problem would go away if the output was a FET transistor instead but a TRIAC is more robust to abuse.

i am glad you aren't the only one that thought a flaw could be in the triac :) ....another analogy of what we call is a "snubber" which really isn't a snubber because snubbers were created to smooth out voltages not get rid of them but anyways take a 1 farad capacitor used for a car....in that kit they give a resistor and small light if you want to drain the capacitor with out using it you hook this resistor and light on the positive probe and connect it to the negative then MAGICALLY the capacitor is drained and has no danger potential and no power stored. (although some kits only come with a resistor) luckily we are not dealing with 1 farad of capacitance otherwise it would take about 2 mins to drain it every time it got recharged.


another method of discharging it would to be to use some arch probe device.(something the short the 2 ends together without the line voltage applied to absorb the charge) although this method is not a very good solution because it would be very temperary and would degrade after each time it had to absorb the voltage

[ErnieHorning]

i am glad you aren't the only one that thought a flaw could be in the triac
I'm not saying that there is anything wrong with the TRIAC, it works the way it was designed to. The issue is when voltage and current get out of alignment with each other. Yes, it really does happen.

If your interested - http://www.pcguide.com/ref/power/ext/basicsPower-c.html

[griffixdc]

I'm not saying that there is anything wrong with the TRIAC, it works the way it was designed to. The issue is when voltage and current get out of alignment with each other. Yes, it really does happen.

If your interested - http://www.pcguide.com/ref/power/ext/basicsPower-c.html

im sorry i wasn't trying to say there was anything wrong with the traic...i am just saying its the flaw of the triac

[P. Short]

Sorry, a scope trace by itself doesn't mean diddly. It's much, much better than talk without any observations at all, but it is just a starting point. I haven't seen any explanation with numbers that supports the observations, including why the transients are present and why they are as big (or small) as they are observed to be. This would need to take into account the characteristics of the SSR, the cabling and the LED string. Without these I consider this to be just hand-waving.

[Reddy_Kilowatt]

Just a guess-

I still only have a handful of LED strings in my display and haven't dissected any of the green blobs. The LED string manufacturer needs to drop the 120V RMS voltage down to a manageable level in the cheapest way possible. One way, might be using a transformerless power supply such as below and could be why the strings look like a capacitive load.


http://www.aaroncake.net/circuits/supply5.gif
http://www.aaroncake.net/circuits/supply5.asp

-Craig

[budude]

Sorry, a scope trace by itself doesn't mean diddly. It's much, much better than talk without any observations at all, but it is just a starting point. I haven't seen any explanation with numbers that supports the observations, including why the transients are present and why they are as big (or small) as they are observed to be. This would need to take into account the characteristics of the SSR, the cabling and the LED string. Without these I consider this to be just hand-waving.

Perhaps - but there were numerous posts of folks saying it fixed their issues completely. Now - was it due to the phenomena explained by chuckd - maybe/maybe not - but it sure seemed to work in many cases. To be fair - it didn't work at all in some cases but again, it's a simple enough experiment/addition to your setup (like - maybe $1 of stuff...) to try it...

[griffixdc]

Just a guess-

I still only have a handful of LED strings in my display and haven't dissected any of the green blobs. The LED string manufacturer needs to drop the 120V RMS voltage down to a manageable level in the cheapest way possible. One way, might be using a transformerless power supply such as below and could be why the strings look like a capacitive load.


http://www.aaroncake.net/circuits/supply5.gif
http://www.aaroncake.net/circuits/supply5.asp

-Craig

even at that instant that would be nice...alot of my LED light strings dont have anything(i know half wave) but they use nothing of the sort of diodes capacitors or resistors in any form series, parallel, bridge, etc....

[Andy.wpg]

The problem with LED strands is that they are simply a far lower load than most SSRs expect, and a fairly nonlinear one, however not one that is significantly inductive or capacity. Since they have far lower load, it is easier for line noise and transients to false-trigger the triacs. Adding some constant nice linear load solves this problem.

That was the explanation I was given by a couple of electronics geniuses that I work with.

Just my 2 cents...


Andy

[griffixdc]

"Adding some constant nice linear load solves this problem."


so if this is the case what would this consist of ?

[P. Short]

"Adding some constant nice linear load solves this problem."


so if this is the case what would this consist of ?

A parallel resistor.

[griffixdc]

A parallel resistor.

so then that goes back to the orginal 'SNUBBER" idea ...except i think some capacitance and transients feed back through other channels as well so shouldn't there be another diode placed in series (on the other channels only with LED strings )

[chelmuth]

C9 Bulb... A Glade Plugin.. A resistor across the output. There have been several things done and have worked for several people.. when you get boards "if" you have a problem experiment then.. up until that point you'll never know if it's going to happen with your situation.

[budude]

As mentioned "SNUBBER" is/was probably not the best choice of words for this since it's normally thought of with motors or relay coils to kill the inductive kick from them. This is not really the same thing but the name for this idea has become common...

[griffixdc]

As mentioned "SNUBBER" is/was probably not the best choice of words for this since it's normally thought of with motors or relay coils to kill the inductive kick from them. This is not really the same thing but the name for this idea has become common...

correct like i stated earlier its actually not a snubber...a snubber stabilizes the voltages . i just use that term because people are familiar with it :)..... the main idea of this thread was to add ideas to my original ideas or to test my ideas to see if they help people that have trouble (after they already included that resistor) :) thanks for all your input (all of you )

[P. Short]

so then that goes back to the orginal 'SNUBBER" idea ...except i think some capacitance and transients feed back through other channels as well so shouldn't there be another diode placed in series (on the other channels only with LED strings )

I don't know the answer, and I don't think that anybody else knows either.

This has not been approached very scientifically, at least not up the the point that I stopped following that thread on PC. Someone had a problem, looked at some signals with a 'scope, and found an ad-hoc fix for the problem that he encountered. His solution worked for some people, and did not work for some other people. I'm not sure that anybody knows (beyond the buzzword level) why it works for some, and not others. I'm not trying to criticize the people involved, because the problem is difficult and expensive to solve. I'm just trying to point out that the problem is not simple. I think that it is likely that there are several different causes (due to varying LED string designs, varying SSR designs and component selections, and other unknown factors), and that solving all of the problems would likely involve travel by someone with the right skills. Not easy, imo.

[griffixdc]

I don't know the answer, and I don't think that anybody else knows either.

This has not been approached very scientifically, at least not up the the point that I stopped following that thread on PC. Someone had a problem, looked at some signals with a 'scope, and found an ad-hoc fix for the problem that he encountered. His solution worked for some people, and did not work for some other people. I'm not sure that anybody knows (beyond the buzzword level) why it works for some, and not others. I'm not trying to criticize the people involved, because the problem is difficult and expensive to solve. I'm just trying to point out that the problem is not simple. I think that it is likely that there are several different causes (due to varying LED string designs, varying SSR designs and component selections, and other unknown factors), and that solving all of the problems would likely involve travel by someone with the right skills. Not easy, imo.

wow very well thought answer i like it ....i wonder if different boards and components on the boards have any effect....well i will let anyone and everyone know if i have a problem when my boards are assembled and then i will act like DEXTER to fix it with my theories :) but if anyone has this problem any suggestions how you fixed it or maybe we can suggest some way to fix it.