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Relay switch jams !!!!


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It's annoying, and saying that nowadays LEDs are common is certainly true. But I'd like to point out a few things:

 

- It's not easy to make a relay with high inrush capability, that fits in the same size module. There are bigger relays that can switch any "nasty" loads. The nastiest of all loads are AC induction motors (pumps). Those relays need to be even bigger. The size is important because you need bigger contacts, bigger spring, bigger coil to "tear open" the welded contacts. The reason you haven't had any problems with ordinary switches, is that you apply much more force to open and close it that those tiny relays.

 

- You can look at it in another way too. The power supply designer should include measures to limit the inrush current. An inrush current is, simply put, a very high current for a very short time, that occurs because the load acts as an "almost short circuit". It's not very easy, partly because people also don't want to have their LED lamps cause radio interference. It's a complex issue and I'm not going to claim that I know all the details. But there is a lot of difference from power supply to power supply (or LED driver, as would be the more appropriate term in some cases).

 

- Rated power and "inrush current" are not the same thing. They are somewhat related, but a relay manufacture will give a separate number on the datasheet. A 20 W LED driver can weld a 1,2 kW relay... Fibaro does not specify both, but subtly remarks in the FGS-222 double relay: "6,5A per channel for resistive load, but total current can not exceed 10A*. Is Fibaro trying to hide the inrush current spec? I really doubt that. You see, it's very difficult to *measure* the current. So that won't help you. Power supply / LED manufacturers sometimes, but certainly not always, mention the current on the datasheet.

 

The easiest solution is adding a bigger relay after the module, but of course... you need some space to do that.

 

I started a long topic with more background on this a long time ago. This is a link to that topic:

 

 

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Yes, I agree on few points . Due to inrush currents , Things go nasty. But also think that what is the point of making relays if we cant use them properly and also what is the point of making such a high rated power relay. Fibaro should consider this matter seriously. They should provide more options like bigger relays for heavy usage and smaller relays for light usage. Not everything is resistive. 

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Yes, I agree on few points . Due to inrush currents , Things go nasty. But also think that what is the point of making relays if we cant use them properly and also what is the point of making such a high rated power relay. Fibaro should consider this matter seriously. They should provide more options like bigger relays for heavy usage and smaller relays for light usage. Not everything is resistive.

 

The only heavy duty Z-Wave switch that I know of is the "Aeon Labs Heavy Duty Switch". I don't own it, but it has been discussed on this forum. Because it is marketed as "40 A resistive", I expect it to have a lot more inrush current capability than the FGS relays. But the current is not specified by Aeon...

 

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The only heavy duty Z-Wave switch that I know of is the "Aeon Labs Heavy Duty Switch". I don't own it, but it has been discussed on this forum. Because it is marketed as "40 A resistive", I expect it to have a lot more inrush current capability than the FGS relays. But the current is not specified by Aeon...

 

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Now i have done one thing . I have connected 5A fuse with the relay ( Fuse with Live wire). Now if it is damaging because of inrush currents, this should prevent it.

I have connected 5 led spot lights of 10W each.

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