Quiet Relay

[ADarkDividedGem]

Hi,

To turn on my kitchen light I use a PIR Sensor Switch which I chose for its ability to detect movement up to 12m away.

It works as described except it makes a loud click when it switches on or off the light which is starting to annoy me. After opening up the case to see if there was any way I could reduce the noise I noticed the noise was coming from the magnet relay switch.

The relay was covered in a plastic casing which I broke open to see what was inside:


I imagine it should be possible to desolder the relay and replace it with one that is quieter


Would anyone be able to suggest a relay that works silently?

 

[JohnW2]

Would anyone be able to suggest a relay that works silently?

Any electromechanical relay will make some noise, although I'm a little surprised that you're worried by the amount of sound that a little one like that would make.

If you want totally silent, your only option would be to use a semiconductor (rather than electromechanical) relay, but you would need a fair understanding of electronics to do that, and you would need to ensure that whatever you used was compatible with the type of light involved.

Kind Regards, John

 

[ADarkDividedGem]

Moving away from an electromagnetic switch would be good. The current one supports a Coil Voltage of 24VDC and a Contact Capacity of 10A 240VAC/28VDC and 5A 125VAC. Any idea how that translates to a solid-state relay?

 

[ban-all-sheds]

I'm a little surprised that you're worried by the amount of sound that a little one like that would make.

I'm surprised he's not encountered other problems with PIR light switches which are far more annoying than a little click.

 

[flameport]

Any idea how that translates to a solid-state relay?

You need a solid state relay which has the same operating voltage (24V DC) and can switch 10A at 240VAC.

It's exceptionally unlikely you can get one the same physical size as the existing, so it will have to be mounted off of the board.

 

[ban-all-sheds]

To turn on my kitchen light I use a PIR Sensor Switch

And you can't use a normal switch because.... ?

which I chose for its ability to detect movement up to 12m away.

You can hear the click from 12m away?

It works as described except it makes a loud click when it switches on or off the light which is starting to annoy me.

Why aren't you long gone when it switches off?

 

[ADarkDividedGem]

It's exceptionally unlikely you can get one the same physical size as the existing, so it will have to be mounted off of the board.

Whats the best method for doing that, do I just solder some wire from the PCB to the switch?

As far as I can tell from the PCB the relay has four legs, when I replace it with a solid state switch which also has four legs how do I know which leg goes where?

 

[ban-all-sheds]

You shouldn't be doing this.

 

[ban-all-sheds]

but you would need a fair understanding of electronics to do that

Or at least enough fundamental understanding of things to be able to see output wires coming from a relay and know which terminals are coil and which contacts, or the nous to just look at the damn thing to see the coil and the contacts.

 

[bernardgreen]

Do you not wonder why the manufacturer used a mechanical relay and not a solid state relay ?

Have a browse through the data sheets for the solid state relays listed click here

 

[Jackrae]

Sounds like a Darwinian case developing

 

[FrodoOne]

Moving away from an electromagnetic switch would be good. The current one supports a Coil Voltage of 24VDC and a Contact Capacity of 10A 240VAC/28VDC and 5A 125VAC. Any idea how that translates to a solid-state relay?

In my opinion, you are much better of having a PIR Sensor which incorporates a relay rather than a solid state relay (SSR)- even if it does make a "click".
The reason is that the relay provides a solid electrical contact whereas a SSR may or may not work with some small loads provided by CFL and LED lamps.

(This is akin to the problems encountered with some dimmers not operating correctly with some supposedly dimmable LEDs.)

However, if you are determined to use a SSR, you would be better of purchasing a new PIR Switch which does incorporate one.
It would probably just as cheap (if not cheaper) than attempting to replace the relay with a SSR,
less time and effort would be involved,
you would have the manufacturers guarantee that it would work (apart for the possibilities mentioned above),
any guarantees you now have would not be voided,
and it is likely to be safer than your best efforts.

 

[ban-all-sheds]

any guarantees you now have would not be voided

Rearrange these words in a common saying:

the bolted stable after locking door horse the has

The relay was covered in a plastic casing which I broke open to see what was inside:
View attachment 131185

 

[JohnW2]

In my opinion, you are much better of having a PIR Sensor which incorporates a relay rather than a solid state relay (SSR)- even if it does make a "click". The reason is that the relay provides a solid electrical contact whereas a SSR may or may not work with some small loads provided by CFL and LED lamps.

Indeed. That is what was in my mind when I wrote the latter part of:

If you want totally silent, your only option would be to use a semiconductor (rather than electromechanical) relay, but you would need a fair understanding of electronics to do that, and you would need to ensure that whatever you used was compatible with the type of light involved.

However, if you are determined to use a SSR, you would be better of purchasing a new PIR Switch which does incorporate one. It would probably just as cheap (if not cheaper) than attempting to replace the relay with a SSR,
less time and effort would be involved .....

Very much so, but the OP might have difficulty in identifying such a device, not the least because a very high proportion do seem to have electromechanical relays (most of them 'click'). In attempting to do the opposite (ensuring that what I was buying did have an electromechanical relay), I have found that (unless one goes very up-market/expensive), information provided usually does not indicate whether or not they have a proper relay, such that the only course is to buy one, try it and see if it clicks!

Kind Regards, John

 

[ban-all-sheds]

I wonder if the click is louder than a light switch makes? How many people are annoyed by those, save light sleepers wrt bathroom pull-cords?

I am very surprised that it's an annoying noise 12m away, I have to say.