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Author Topic: Fibaro Double Relay Switch Module - FGS221 - LED Load  (Read 13860 times)

Offline silasbruder

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #15 on: February 09, 2015, 06:06:04 am »
Hi, I am having the same problem in different clients, I just read this post and i will try the suppressor between O1 and N.
Using a contactor wouldn`t help aswell? Or the only solution is the suppressor?

King Regards

Offline RexBeckett

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #16 on: February 09, 2015, 02:13:44 pm »
Quote
Using a contactor wouldn`t help aswell?

It would if the contactor was rated for a large-enough reactive load. It is sometimes necessary to fit snubbers/suppressors to contactors, though. Also the coil of a contactor is largely inductive and, if it is a large one, may still require a suppressor to protect the contacts of the Z-Wave switch.

Reactive loads cause many switching problems...
 

Offline balboa

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #17 on: July 06, 2015, 03:03:30 pm »
Hi. I'm having the same problem. I've already connected a snubber with C=100nF(X2) and R= 100 ohm (3W) to O and N, and it didn't work. Am I doing something wrong? Info: 230V supply connected to a LED strip (with drive - 12V - 7,2W/m); 0,835A nominal at the switch.

Offline Alexia

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #18 on: July 21, 2015, 07:23:42 am »
Has anyone really overcome this problem using snubber or any other simple solution?
« Last Edit: July 21, 2015, 07:25:24 am by Alexia »

Offline rotman253

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #19 on: November 20, 2015, 10:56:12 am »
Hey ,
so glad I stumble upon this thread , I thought my fibaro relay is gone.
knocking on the relay released the relay.

so can someone please explain what exactly should I buy and connect to the fibaro relay in order to solve this issue?

Thanks

Offline KMorley

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #20 on: December 03, 2015, 07:24:40 am »
I have an engineering background and this is an interesting problem, so I thought that I would chime in ;)

It sounds like arcing is causing the relay contacts to stick together in the closed position regardless of the relay actuator.  The root cause of the problem may be that the contacts are made of some soft/easily melted material, which inherently makes that material a poor choice for use as relay contacts.  Simply put, the root cause of the problem may be poor design of the relay.

The power supply may be a contributing factor as it may have a high inrush current that significantly exceeds the design of the relay.  I don't know what kind of power supply is being used for this, but high inrush current is a characteristic of conventional, non-switching type power supplies.  Correctly-size switching power supplies should not have the same problem or at least not to the same degree.  A properly-sized resistor placed in series with the power supply should help reduce in-rush current.

The power supply design may also have some reactive/inductive design that causes an arc when the contacts open.  This particular issue is characteristic of conventional non-switching power supplies that have a transformer primary wired across the mains.  A disk capacitor placed across between the two relay contacts should suppress arcing when the contacts open.  Adding a gas tube in parallel with the capacitor would also help.  Gas tubes are fairly slow to ionize, so the capacitor would be mandatory and the gas tube would just provide additional suppression.

Rather than analyze and experiment, it might be better to eliminate the problem by adding a Solid State Relay (see https://en.wikipedia.org/wiki/Solid-state_relay).  Use the Fibaro relay contacts to send mains voltage to control the SSR and let the SSR do the heavy lifting to start/stop the power supply.  SSRs have an inherent advantage in that when they switch mode (on to off or vice versa), they do so during the mains sine wave zero crossing point.  At the zero crossing, there is zero voltage and current available on the mains and so there is no current in-rush or high-voltage inductive arc possible.

SSRs are relatively cheap and effective.  Additionally, it should be easy to retrofit to the existing configuration - at least for testing and experimentation purposes.

Ken


Offline ohdan

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #21 on: July 19, 2017, 06:48:55 am »
In case anyone still wants to resurrect their Fibaro FGS221 and FGS222 double relay, I connected a thermistor in series from the "light" to the relay. The thermistor prevents the surge of current when the switch is turned on (inrush current) and prevented the contact points of the Fibaro relay from welding together.

Please use with care as thermistor runs hot so when you put it back into the socket box, do make sure there is some distance between the thermistor, wires and the relay itself.

Offline Cor

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #22 on: July 19, 2017, 08:25:22 am »
I have this issue as well occasionally on one of my relais , and always with the same lights- relais.

Do you have some more info about this thermistor.

Thanks,
Cor

Offline ohdan

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Re: Fibaro Double Relay Switch Module - FGS221 - LED Load
« Reply #23 on: July 19, 2017, 11:17:09 am »
There you go...

http://uk.farnell.com/ametherm/sl15-10006/thermistor-ntc-radial-10ohm/dp/2113005

My AC supply is at 220V/240V so this thermistor should be suitable for UK use as well.