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dimmer 2 problems, flickering lights


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i did a complete toilet renovation and i decided to use a dimmer 2 for the lights, so there was no need to install the blue (neutral) wire.

when i install the dimmer 2 the lights flicker continuesly, even if the dimmer is off.

even the green led on the module itself goes on and off.

 

hc2 message: [19:24:58] ID 435: Voltage Drop/Drift. Reduce the maximum brightness level.

 

that is not correct, voltage is around 225 volt and when i connect the lights directly the lights are burining bright and steady.

 

someone any ideas? thoughts? anything?

 

 

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On 12/17/2018 at 8:03 PM, mohammad abu hantash said:

does the SSR safe to install over the ceiling, since my wall box is too small, does they heat up if the circuit is on for long time

 

Yes, they will heat up, depending on the load. They will heat up more than ordinary relays!

 

Your electrician should be able to tell you what is acceptable or not. Regulations are a local thing. I can only talk with confidence about regulations in Belgium and some "general best practices".

 

Your electrician is responsible! Not me or any other forum member...

 

On 12/17/2018 at 8:03 PM, mohammad abu hantash said:

as i understand double switch need double SSR one for each switch right ?

 

Yes.

 

BTW You won't get energy/power measurement with this setup because the FGS "does not see the load".

 

On 12/17/2018 at 8:03 PM, mohammad abu hantash said:

A-  arc suppressor snubber

 

Not an "inrush suppressor" and not relevant when we talk about "sticking or welding of relay contacts".

 

Snubbers are used to suppress arcs when contacts open. Inductive loads like solenoids, motors transformers can cause extra wear because of arcing. BTW The FGS is not rated to do inductive loads...

 

On 12/17/2018 at 8:03 PM, mohammad abu hantash said:

B- SSR

 

A type of electronic relay. The advantage is: no moving parts. Disadvantage: higher power losses, and overloading destroys them (fuses are not fast enough to protect them). When you switch currents above a few  Ampere, a heat sink is necessary and will make it (very) bulky. Your electrician should consult the datasheet.

 

I don't think anyone has ever posted anything on SSRs on this forum! This means it is not popular!

 

I am not even sure if it would work, because  (a) the FGS passes a small current (depending on the model, I have never tested it but some users have reported this...) when it is open and if the SSR has a sensitive input it might not turn off. To Be Tested. And (b) A SSR most likely contains a snubber (see answer to your first question) so it also passes a small current to the load, which might cause LED lamps to glow or flicker. The leakage is mentioned in the datasheet. Again: "To Be Tested".

 

On 12/17/2018 at 8:03 PM, mohammad abu hantash said:

Einschalt strombegrenzer ESB1 you can check it from this link

Please login or register to see this link.

 

This device lowers the inrush current, a few users experiencing welded contacts have told me it works for them. I believe them, it makes sense. I cannot predict if it will work for you... Your electrician should be able to understand the datasheet, For the technically inclined: it is an NTC + a fuse. I have several older post about inrush current, if anyone should be interested...

 

Welding af contacts happens because of high inrush current on small relays because of contact size but also because of weak spring to pull open the contacts.

 

Here are some of my relays. The one on the left is an SSR + cooler, I use it to switch a 16 A load.

 

The smallest white relay is similar to the one's used in modules like the FGS (rated about 8 A resistive load".

 

The bigger white relay is the one used in some Wall Plugs. It has about 3x the volume of the FGS relay and it can handle small motors.

 

The black one, bottom right, is similar to the relays used in Aeotec's heavy duty switch. It can handle both large resistive and inductive loads. It is a latching relay, it does not use a spring to change position (it uses 2 coils, or one coil and a pos/neg pulse to open/close).

 

The grid on the mat is 1 cm.

 

 

Please login or register to see this attachment.

 

Edited by petergebruers
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@petergebruers thanks a lot for the answers you mentioned but i have the following notes :

  • LED power saving non dimmable spot lights is something really common these days, why does this is not supported out of the box on the relays ? is it bad design ?
  • How can i guarantee setup to make the relay not welding if i use it with mutliple non dimmable LEDs connected on the same zone say '20 LED with transformers'
  • is there any manufacturer other than fibaro have something better for wall switches all which i need is ON/OFF for my lights on home is that too complex ?
  • i checked some manufacture where they have bigger wall switches (do you think they suffer from welding also? or they will have stronger and bigger spring ? :

    Please login or register to see this link.

All i need is just to eliminate any solution that will not work off course my electrician will do that under his warantee just i want to make sure i don't wast time and money on trial and error.

' FGS is not rated to do inductive loads...  ' so they will not work with the LEDs and dimmer have issues with non dimmable LED's what should i try ?

 

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55 minutes ago, mohammad abu hantash said:

LED power saving non dimmable spot lights is something really common these days, why does this is not supported out of the box on the relays ?

 

I agree, that's something really frustrating.

 

IMHO the transition from incandescent to LED went very fast in a few years time.

 

I think one could argue the LED DESIGNERS should have made their "inrush current" lower...

 

A normal light switch also can weld because of bad LED design, but you can apply a lot of force to get it un-stuck.

 

If you look at the relative sizes of the relays in my previous post... It simply is not possible to fit 2 big relays in a module that has to be compatible with boxes and space behind existing switches.

 

Someone contacted me, because his circuit breakers would trip if he turned on all his power supplies (to LED strips) at ones. Regulations usually do not permit to increase the rating of the breaker, so the only solution is splitting the supplies in 2 parts and turn them on separately.

 

Alternatives to relays? They do not really exist. The FGD212 uses an electronic switch and this limits the controlled output to about 1A (because of heat losses, robustness and - again! - inrush current capability). The reason is, high voltage mosfets have high "on resistance". A lot of progress has been made, using exotic materials and designs, but I don't expect a 10 A mosfet dimmer of the same size as the FGD212 soon...

 

 

55 minutes ago, mohammad abu hantash said:

is it bad design ?

 

 

 

Those modules are small... They could make them bigger but then won't fit behind existing switches.

 

The FGS 223 has "zero cross switching" which should help.

 

Fibaro is very unclear about the capabilities of that module, in fact they still spec "resistive loads".

 

If people talk about welded contacts, it is mostly on older models. Though it can still happen on this 223... There have been a few reports.

 

55 minutes ago, mohammad abu hantash said:

How can i guarantee setup to make the relay not welding if i use it with mutliple non dimmable LEDs connected on the same zone say '20 LED with transformers'

 

It is very hard to predict because inrush current has many definitions and is often not even on the data sheet.

 

If those 20 LED transformers are of the same type I use (I am not going to give the brand, they make 1000s of supplies) on my LED strip, that is a 60 Watt 24 V DC SMPS, the peak current of this supply is 60 A.

 

If I switch on 20 x 60 A = 1200 A that is going to trip the circuit breaker. It is probably going to trip the main circuit breaker as well! We're not even talking about relays...

 

For such a situation, multiple DIN rail mounted relays for lighting are recommend.

 

In some countries they call these big relays "contactors". Here is an example.

 

 

I say "DIN" mount because bigger relays may "hum" so you might hear them if you put them in the ceiling.

 

55 minutes ago, mohammad abu hantash said:

is there any manufacturer other than fibaro have something better for wall switches all which i need is ON/OFF for my lights on home is that too complex ?

 

The single relays are usually bigger... I am not sure if that helps.

 

55 minutes ago, mohammad abu hantash said:

Please login or register to see this link.

 

On that page I read: MH-S311H and MH-S312H. That "H" seems to matter. In the manual:

 

Resistance load: 2*10A
LED load: <10A each channel, inrush current 165A/ 20ms

 

So you have to be careful, resistive load means you have to take into account the "power factor" or "cos phi" of your load. This should be on the data sheet of your led or transformer. Let us assume it has no active PFC and it has "PF 50%" then this relay can only switch a continuous load of 5A of this particular type of power supply.

 

How many of my LED strips can it handle? Remember, my power supplies...  60 Watt 24 V DC SMPS, the peak current of this supply is 60 A.

 

That module is guaranteed to switch 2 of those supplies. Three supplies would mean 180 A inrush = 10% above spec...

 

I cannot tell you anything else about these modules. I don't own them and I don't follow posts about this model.

 

EDIT: for sake of completeness... A 40A TRIAC based Solid State Relay (SSR) can, rule of thumb, handle 400 A inrush current (Non repetitive surge peak on-state current, see datasheet). Because they can do "zero cross switching" they can handle higher capacitive loads... Still, the total capacitance has its limits.

 

Edited by petergebruers
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@petergebruers thanks alot for your time and detailed explanation i don't know if my electrician have the tools to measure the inrush current of each zone , i talked to him and he said the device that is used to get exact inrush current is too big and used in big factories where they have huge loads.

 

i can't even understand how does 2watt,  200 mAmp transformers can cause this issue when they startup, but i think i got just one switch welding not both on the dual switch 2 this might because the second zone have more transformers ?

 

also why does the circuit breaker does not go down if that load is too much the main circuit breaker for that zone is just 16 Amp and we are talking about 160 AMP for 20 sec .

 

one electrician said that the stuck reason might be because of electromagnetic field around the coils and they suggested to installer diode does that make sense ?

 

 

Edited by mohammad abu hantash
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6 minutes ago, mohammad abu hantash said:

i don't know if my electrician have the tools to measure the inrush current of each zone , i talked to him and he said the device that is used to get exact inrush current is too big and used in big factories where they have huge loads.

He's not joking. Measuring inrush is difficult. With an oscilloscope, a non-inductive load and careful setup I could tell what the inrush is "in my house" (with a large error margin). But I cannot tell how much it would be in your house, because you have different wiring, maybe longer connections to the closest transformer. Some Fluke meters, used to diagnose motors, can do that but they use a specific definition of "inrush current". I do not own such a device and cannot tell you much about it.

 

I am very close to the nearest power transformer (about 100 - 150 meter) and this means I can have very high currents, I estimate 600 - 1000 A is possible. If you live in a remote area and far from a transformer, inrush might be much lower!

 

12 minutes ago, mohammad abu hantash said:

i can't even understand how does 2watt,  200 mAmp transformers can cause this issue when they startup

 

I think 2 Watt supplies cannot cause the FGS to weld, it would surprise me. I'd say it starts at about 10 Watt and I have 20 Watt supplies that cause trouble on the older FGS-221. I don't know if they would cause trouble on FGS-223 though.

 

May seem weird to say... it is simply mostly Ohm's law, that's all you need to get an idea!

 

When you "start" a power supply, you have to charge a capacitor. En empty capacitor is (nearly) a short circuit.

 

So what current can you expect if you are at the peak of the sine wave?

 

I = U / R

 

U = 325 V

R = resistance of the wires in your house + resistance to the power substation, about 0.5 ohm in my case. Plus the ESR (effective series resistance) of the capacitor, which might be around 3 ohm. Total resistance = 3.5 ohm.

 

I = 325 / 3.5 = 90 A.

 

So a 60 A inrush current spec for a 60 W power supply is not too far off. While the active current of that supply is only around 250 mA

 

These calculated numbers are not exact, but they give you an idea, an order of magnitude.

 

21 minutes ago, mohammad abu hantash said:

also why does the circuit breaker does not go down if that load is too much the main circuit breaker for that zone is just 16 Amp and we are talking about 160 AMP for 20 sec

 

Not 20s,  but 20 milliseconds. 

 

Circuit breakers have a "fast" component, to protect against short circuit. And a "slow" component to protect against overheating of wires and cables.

 

The "I nominal" determines limits of operation and is based on the slow component. In = 16 A in your case.

 

This curve tells you what happens if you apply an overload.

 

According to this curve, a 16 A type C will not turn off with inrush < 80 A but it is guaranteed to turn if inrush > 160 A and lasts long enough.

 

The inrush current might be very short, then it also does not trip the breaker, it is a mechanical system and it has some inertia.

 

When you apply 32 A it will trip after roughly 10 to 100 seconds.

 

Please login or register to see this image.

/monthly_2018_12/CircuitBreakerC.jpg.323cdd24c550a7b5051417eea03ba7f8.jpg" alt="CircuitBreakerC.jpg.323cdd24c550a7b5051417eea03ba7f8.jpg" />

 

32 minutes ago, mohammad abu hantash said:

one electrician said that the stuck reason might be because of electromagnetic field around the coils

In industrial settings, with large fields that might happen. Maybe if you stick a neodymium magnet close to the relay, but that seems rather academic to me.

 

The metal of the contacts melts when they touch (because the area is tiny) and then cools, then sometimes they stick. In fact, all relays that carry a reasonable amount of current (I am not talking about small signal relays) melt and that is what makes the resistance so low. The spring must break the weld.

 

33 minutes ago, mohammad abu hantash said:

they suggested to installer diode does that make sense ?

 

Not sure what he means.

 

On the coil side you will find a diode, to protect the transistor at turn off. Without this diode the transistor would probably fail. It is there...

 

On the load side, I cannot really see how you could add a diode, because the load is AC.

 

Unless he is talking about "transient voltage suppressors" which are a special kind of diode. They exist in a bidirectional form (and I use them that way). Useful to protect agains over-voltage transients, but not against inrush.

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9 minutes ago, petergebruers said:

He's not joking. Measuring inrush is difficult. With an oscilloscope, a non-inductive load and careful setup I could tell what the inrush is "in my house" (with a large error margin). But I cannot tell how much it would be in your house, because you have different wiring, maybe longer connections to the closest transformer. Some Fluke meters, used to diagnose motors, can do that but they use a specific definition of "inrush current". I do not own such a device and cannot tell you much about it. 

 

I am very close to the nearest power transformer (about 100 - 150 meter) and this means I can have very high currents, I estimate 600 - 1000 A is possible. If you live in a remote area and far from a transformer, inrush might be much lower!

 

 

I think 2 Watt supplies cannot cause the FGS to weld, it would surprise me. I'd say it starts at about 10 Watt and I have 20 Watt supplies that cause trouble on the older FGS-221. I don't know if they would cause trouble on FGS-223 though.

 

May seem weird to say... it is simply mostly Ohm's law, that's all you need to get an idea!

 

When you "start" a power supply, you have to charge a capacitor. En empty capacitor is (nearly) a short circuit.

 

So what current can you expect if you are at the peak of the sine wave?

 

I = U / R

 

U = 325 V

R = resistance of the wires in your house + resistance to the power substation, about 0.5 ohm in my case. Plus the ESR (effective series resistance) of the capacitor, which might be around 3 ohm. Total resistance = 3.5 ohm.

 

I = 325 / 3.5 = 90 A.

 

So a 60 A inrush current spec for a 60 W power supply is not too far off. While the active current of that supply is only around 250 mA

 

These calculated numbers are not exact, but they give you an idea, an order of magnitude.

 

 

Not 20s,  but 20 milliseconds. 

 

Circuit breakers have a "fast" component, to protect against short circuit. And a "slow" component to protect against overheating of wires and cables.

 

The "I nominal" determines limits of operation and is based on the slow component. In = 16 A in your case.

 

This curve tells you what happens if you apply an overload.

 

According to this curve, a 16 A type C will not turn off with inrush < 80 A but it is guaranteed to turn if inrush > 160 A and lasts long enough.

 

The inrush current might be very short, then it also does not trip the breaker, it is a mechanical system and it has some inertia.

 

When you apply 32 A it will trip after roughly 10 to 100 seconds.

 

Please login or register to see this link.

 

In industrial settings, with large fields that might happen. Maybe if you stick a neodymium magnet close to the relay, but that seems rather academic to me.

 

The metal of the contacts melts when they touch (because the area is tiny) and then cools, then sometimes they stick. In fact, all relays that carry a reasonable amount of current (I am not talking about small signal relays) melt and that is what makes the resistance so low. The spring must break the weld.

 

 

Not sure what he means.

 

On the coil side you will find a diode, to protect the transistor at turn off. Without this diode the transistor would probably fail. It is there...

 

On the load side, I cannot really see how you could add a diode, because the load is AC.

 

Unless he is talking about "transient voltage suppressors" which are a special kind of diode. They exist in a bidirectional form (and I use them that way). Useful to protect agains over-voltage transients, but not against inrush.

 

thanks a lot for that, you helped me to understand everything about that, so for conclusion i have to make multiple tries to control the LED's from fibaro relay.

i will ask my electrician to start with what he see reasonable and safer to install.

 

lost of fans here suggested that they solved the issue by installing another relay after the Fibaro relay, i said that to my electrician and he said yes this looks logical things i don't know if it will work 'i have to test that'

BTW the welding happen only on fast switching i don't see the issue if i did slow switching for the relay i mian by fast switching i go to the switch and start do 'on then off then on then off ..."

sometimes it weld i did that for testing because i noticed that the relay is slow somehow in switching the light on 'I hear the tick sound from relay but the lights take small delay to turn on'

 

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19 minutes ago, petergebruers said:

I Agree to all of that. 

does second relay have to be solid state one or mechanical relay is there any good brand that lasts for long period without replacement since the electrician might install it over the ceiling

 

19 minutes ago, petergebruers said:

A lot of them use an NTC to limit inrush. The NTC is a resistor, but when it heats its resistance drops. The idea is: limit current at the start, but don't limit it when the supply is operational. 

  

It is a reliable solution with one downside... If you turn off the supply, the NTC is still hot. You have to let it cool and that can take 30 - 60 seconds (order of magnitude) to let it regain some resistance and work as an inrush limiter. 

 

If you turn off the relay... Then wait until the LEDs are off , which means the capacitor is empty again, but before the NTC has cooled, then the next turn-on might cause a higher peak than expected. The voltage at turn-on can be anything between 0 and 325 V. The FGS-223 and FGD-212 would wait until it is 0 but the older modules don't do that. 

yes also i found that also on community, i have the FGS-223 and yes it support zero crossing, if i want to go on this solution do i have to install one NTC per LED or one for all of them on the wall box ?

 

imagine this scenario if i turned the switch on then after 1 hour turned it off , then within 15 sec turned it on again the NTC is still not cooled does the FGS-223 state will be on and the lights will be off for around 15-45 second then they will turned on? is that what you mean if that the case its not big issue i think

 

@petergebruers can't thank you enough for your great support

 

Edited by mohammad abu hantash
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