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daviddth
06-21-2009, 12:47 PM
Is there any reason you can think of that 2 SSR's could not be placed in parallel, supplying 1 light?

I'm thinking of using motion sensors to trigger LED Floodlights. I know this can be done without an SSR, but.... My security system also has a panic button, as well as a light buttion on the keypads and remote keys, so I was considering connecting that up to a second SSR, so eithor the motion sensor, OR alarm system can be used to turn the LED lights on outside.

TERBObob
06-21-2009, 01:31 PM
Not sure about over there in Oz , but here in the states ... there are two lines that come into your house , which , creates your 220 line . And , if you used both lines for the output from the SSR's , then you would not be getting 110 only , you would get 220 instead . Again ... I'm not sure how the "juice" flows over there , so , to be honest , it might be something you need to check into a little deeper .
Here , its 2 seperate 110 lines , with same common , which , when the hots are joined , gives you 220 instead of the 110 .

daviddth
06-21-2009, 02:49 PM
Totally different here. 240V from any Active to Neutral. Most people dont need to use more than 1 phase, and dryers, heaters etc usually just use 240V

I'm talking about from Active, through 2 SSR's in parallel, to the load. The idea being eithor SSR could trigger load, in this case the lights, and they will only be running at 24V DC, but I could switch the 18V AC side if needed. I guess the best way would be to try it like I usually do here :)

budude
06-21-2009, 02:49 PM
Perhaps it would be better to have two inputs into the SSR Opto instead of playing with the AC side? It only requires pulling the inputs to ground as I recall so a parallel switch could do this I think.

You could run into some major issues if you get the neutrals and hots mixed on the two... :!:

daviddth
06-21-2009, 03:40 PM
Good point, although fused at 5A, and 24V DC (Or 18V AC) the bang is not as bad as a 20A 110V or 18A 240V setup :) Then again I usually only run the actives through the SSR's, and keep neutrals seperate - that saves simple mistakes. Same goes for DC gear - it's always Red & Black, or Grey & Black, and the blacks are usually kept seperate from the board (The LED Floods were a little different to minimise additional wiring joins, plus there were all soldered, not screw connections)

Parallel switchgear is pretty simple for me - I was more worried about the triacs behaviour on the one not switched (Same with the DC SSR's).

bcadman
06-21-2009, 04:01 PM
Two triacs in parallel should not be a problem; however, I also think the idea of two triggers (pulling down) the opto is a good idea .

Virtus
06-21-2009, 04:25 PM
I have the same question from a US standpoint. Assuming the 110VAC supplied through each SSR is from the same branch is there any problem induced back to SSR2 when only SSR1 is activated? Any issue if Trigger 1 and 2 are activated at the same time?

daviddth
06-21-2009, 11:47 PM
Virtus - thats the exact setup I am after. I'm heading to the shed & will probably rough something up for an extended test today. Nothing quite like sitting things in the middle of the concrete floor, fireproof cable supplying it, for a test for a few days... Ahhh reminds me of the early 6 way 240V SSR controlled powerboard days :)

RPM
06-22-2009, 12:39 AM
I have the same question from a US standpoint. Assuming the 110VAC supplied through each SSR is from the same branch is there any problem induced back to SSR2 when only SSR1 is activated? Any issue if Trigger 1 and 2 are activated at the same time?

IMO it would make more sense to use the low voltage DC side of the SSR, then isolate the sources with something like an 1N4001 diode. This would eliminate any possible mishaps on the high voltage side ;)

Just my two cents...

Robert

Matt_Edwards
06-22-2009, 03:00 AM
if you are using DC SSRs then No problems as they are low side switches.

Matt

Macrosill
06-23-2009, 08:20 AM
I have the same question from a US standpoint. Assuming the 110VAC supplied through each SSR is from the same branch is there any problem induced back to SSR2 when only SSR1 is activated? Any issue if Trigger 1 and 2 are activated at the same time?
I have done this in the past, not with ssrs but with toggle switches. This was for a person who had security motion lights but also wanted the ability to manually turn on the lights if they heard a noise. As long as the same feed is used for both sides of the parallel relays there is no danger of sending 240v to the light. However there is an inherent danger. If working on the light and you turn off the switch there is still the possibility of the other switch, or ssr in this case, can be supplying power to the light. BOOM, you get zapped. Unless of course you are very diligent and turn off the power from the breaker before hand. This is assuming you utilize the same branch circuit for the feed on both relays. It is possible to utilize 2 different branch circuits for the 2 relays but still keep them on the same phase. It would work properly but there is a much greater chance of the last scenario occurring.

Virtus
06-23-2009, 11:43 AM
I have done this in the past, not with ssrs but with toggle switches. This was for a person who had security motion lights but also wanted the ability to manually turn on the lights if they heard a noise. As long as the same feed is used for both sides of the parallel relays there is no danger of sending 240v to the light. However there is an inherent danger. If working on the light and you turn off the switch there is still the possibility of the other switch, or ssr in this case, can be supplying power to the light. BOOM, you get zapped. Unless of course you are very diligent and turn off the power from the breaker before hand. This is assuming you utilize the same branch circuit for the feed on both relays. It is possible to utilize 2 different branch circuits for the 2 relays but still keep them on the same phase. It would work properly but there is a much greater chance of the last scenario occurring.

Thanks!

daviddth (http://doityourselfchristmas.com/forums/member.php?u=111),
Any update on your test(s)?