Solid State Relays Not Working!

[JameZZ]

Evening All

I have 3 solid state relays that I used a couple of years ago for a lighting project to switch 240V lights on using 24V control.

They have been in the shed since then, but I have just set them up with some some 12V lights, using the same 24V transformer & two of them don't work at all, and one just makes the bulb flicker dimly. I've tried 2 other control transformers and they have the same result. I have the polarity the correct way & they are DC.

Could it be the cold winter that's broke them? It's just strange they all wont work!

Or is it that you can only control 240V stuff?

Thanks

 

[audi100]

Have you measured the actual voltage coming from the transformer?
I assume its 230volt primary and 24 v secondery.

 

[flameport]

The load terminals will have a minimum voltage which is required to operate correctly, for a 240VAC type, this will probably be around 50VAC.
Trying to control voltages below that, or DC won't work.

 

[sparkticus]

Some solid state relays only switch AC on the load side and some are TRIAC or SCR based. 12 volts is only just over 5% of mains voltage so you could be operating on the lower ragged edge.

Dry contact relays have a finite life but are quite universal provided they are not overloaded for a given application.

Can you send the model and type of your solid state relay?

 

[JameZZ]

The load terminals will have a minimum voltage which is required to operate correctly, for a 240VAC type, this will probably be around 50VAC.
Trying to control voltages below that, or DC won't work.

Oh dear

Do you know an alternative component that will do the same thing but switch a voltage of around 10V? I don't really want to use a normal relay if I can help it because there going to be turned on and off quite quickly...

Thanks

 

[JameZZ]

Some solid state relays only switch AC on the load side and some are TRIAC or SCR based. 12 volts is only just over 5% of mains voltage so you could be operating on the lower ragged edge.

Dry contact relays have a finite life but are quite universal provided they are not overloaded for a given application.

Can you send the model and type of your solid state relay?

It just says Crydon Solid State Relay,

Output - 480V 25A

Input 2-32V DC

Thanks

 

[sparkticus]

The load terminals will have a minimum voltage which is required to operate correctly, for a 240VAC type, this will probably be around 50VAC.
Trying to control voltages below that, or DC won't work.

Oh dear

Do you know an alternative product that will do the same thing but switch a voltage of around 10V? I don't really want to use a normal relay if I can help it because there going to be turned on and off quite quickly...

Thanks

How quickly? What frequency?

 

[JameZZ]

The load terminals will have a minimum voltage which is required to operate correctly, for a 240VAC type, this will probably be around 50VAC.
Trying to control voltages below that, or DC won't work.

Oh dear

Do you know an alternative product that will do the same thing but switch a voltage of around 10V? I don't really want to use a normal relay if I can help it because there going to be turned on and off quite quickly...

Thanks

How quickly? What frequency?

Depends, its for spot light sequencing for a show. So like 3 lights sequencing 1, 2, 3, 1, 2, 3 depending on the music really.

It's not a permanent thing, just for the one time.

Thanks

 

[sparkticus]

Some solid state relays only switch AC on the load side and some are TRIAC or SCR based. 12 volts is only just over 5% of mains voltage so you could be operating on the lower ragged edge.

Dry contact relays have a finite life but are quite universal provided they are not overloaded for a given application.

Can you send the model and type of your solid state relay?

It just says Crydon Solid State Relay,

Output - 480V 25A

Input 2-32V DC

Thanks

These will not reliably switch 12V DC unless the load is very low impedance. No good for switching 12V lamps.

 

[sparkticus]

For a load up to 10 watts these are good.
http://uk.rs-online.com/web/p/reed-relays/2562336/


these are 30 watt switching
http://uk.rs-online.com/web/p/reed-relays/3491825/


Both will switch absolutely fine at your frequency range.

There are other (probably better) ways to switch DC lights by using a bipolar transistor or an SCR but that requires additional control circuitry.

 

[bernardgreen]

My preference is the OPTO22 range The ODC5 will switch 12 volts up to 3 amps. ( or more but that is over its spec ) 5 volt control signal but with resistor in series can be higher,. ( G4ODC24 is 24 volt control )

http://www.opto22.com/site/pr_details.aspx?cid=4&item=ODC5

http://www.opto22.com/site/pr_details.aspx?cid=4&item=ODC24

They have their own pin arrangement but OPTO22 also make 4 module PCB with all the necessary terminals. RS Components 2508644068 Manufacturer Opto 22 Mtfr. Part No. G4ODC5

Other compatible makes are available but I find OPTO22 the best.

 

[sparkticus]

My preference is the OPTO22 range The ODC5 will switch 12 volts up to 3 amps. ( or more but that is over its spec ) 5 volt control signal but with resistor in series can be higher,. ( G4ODC24 is 24 volt control )

I must admit they are the "Rolls Royce" of solid state relays. I use them for industrial machine control. Rarely let you down and lots of interconnect methods available for them.

 

[bernardgreen]

Forgot to add the UK agents details

System Devices UK, Ltd.
1 Beeston Court, Manor Park
WA7 1SS Runcorn, Cheshire
United Kingdom
Phone: +44 (0)1928 571 977
Fax: +44 (0)1928 571 988
www.systemdevices.co.uk
[email protected]

 

[JameZZ]

Thanks everyone, very helpful as ever