AC input solid state relay (SSR)

**Al in Raleigh** · 10-16-2009, 12:26 PM

Some people that I have spoken to want to switch motors and large current loads using LOR or other controllers. That is difficult to do. Here is a solution. Use an AC input SSR. SSRs are not unusual but the SSR below is very unusual in that the input is AC which means you connect the output of your controller channel directly to the input of the SSR. Most SSRs are DC input. The SSR below can control up to 25 amps (with proper heatsinking). I use these to control motors in my display. When you use a relay or SSR you will not be able to ramp the voltage of the channel which isn't a problem for AC motors. AC motors will self-destruct if you try to ramp the voltage to them.

Here is the Ebay link to the SSR. This is a spectacular price:
http://cgi.ebay.com/ws/eBayISAPI.dll...E:B:SS:US:1123

Here is the datasheet:
http://www.datasheetarchive.com/pdf-...DSA-141561.pdf

Al

**kidcole** · 10-16-2009, 01:49 PM

I sent a message to the seller asking for a quantity price. With luck he might have a bunch. I can make the group buy for us and distribute them. I need 2 right away, but might buy 4 at this price. I seem to recall these were in the mid-20s when we discussed them in September ..

I can also get some great vapor-chamber type heatsinks when we trash them in the lab - I am sorry but the best price I can offer for those is $0.

**Al in Raleigh** · 10-16-2009, 09:42 PM

Thanks Denny. This style SSR is rare and expensive. If I posted this on PC the vendor would sell out in minutes.

**mschell** · 10-17-2009, 06:14 PM

Denny,
I'm in for at least 2-3 of those SSRs, and would be interested in some heatsinks, too!

Mark

**kidcole** · 10-18-2009, 08:26 PM

I have found two dealers. But so far have not received a reply from either one. Typical for eBay. It amazes me how many people are selling something but spend zero time replying to emails (to help sell their items). I will keep you posted.

**rcktpwrd** · 11-13-2016, 07:51 PM

I know this an old thread but I am looking into getting some relays to control inflatables and maybe some other stuff using LOR. Unfortunately the eBay link isn't good anymore and there is no other information about the SSR linked to.
Basically I want to use a couple of channels on a controller to turn the inflatables on when the show starts and then off at the end of the show. This way we don't have to run separate timers and can have everything go on and off at the same time.
Anyone have any info or ideas?

**rcktpwrd** · 11-13-2016, 10:05 PM

would something like this work?

AC 110/120V Coil DPDT 8 Pin Red LED General Purpose Power Relay w Socket | eBay

or this:
110-120V 2NO Coil Volt 16A Double Pole Electric Power AC Contactor Block | eBay

**rcktpwrd** · 11-13-2016, 11:03 PM

I have found these as well:

Crydom A1225 Solid State Relay 120V 25A Output 280V 90A Input | eBay

I'm just not sure on how it would be wired into the circuit.

**kidcole** · 11-14-2016, 03:19 PM

Originally Posted by rcktpwrd

I have found these as well:

Crydom A1225 Solid State Relay 120V 25A Output 280V 90A Input | eBay

I'm just not sure on how it would be wired into the circuit.

Yes this is the type of SSR you need, not the relay type. The wiring is pretty simple. You put your SPT2 wire across poles 3 and 4, and hook it up to your controller channel. Be sure to set that controller channel in your software so that dimming is not allowed. 3 is Neutral and 4 is Hot (load). Then for the LOAD (or output) side of the SSR, you wire poles 1 and 2 to break the hot wire of an extension cord. Plug the extension cord directly to a power outlet and plug your high amperage (or inductive load such as a blowup blower motor) into the extension cord end.

They way I have made these in the post, I literally used a full extension cord. Then decide where you want the SSR to sit on the cord. Usually closer to the plug end is what I do. Carefully cut open the jacket of the extension cord to expose a few inches of the wires inside. Cut the hot wire and connect it to poles 1 and 2. I suggest that your solder some spade lug connectors to the ends of the wires to be sure that that circuit is safe. Then put the whole thing inside a small gadget box. Use screw down tie wraps to make sure that none of the wires can be pulled from the outside. Strain relief is important to made a safe SSR box. Do the same for the SPT wire that you hook up to poles 3 and 4. I usually put a very short male plug on the SPT wire only a foot or two outside the box. Then you can customize another extension cable to reach from your controller to the SPT plug.

The way this works is when you apply 110v to the input side, the output closes (hot wire only) to fire up your load. Do not dim the input. Just turn it on or off.

If you are not comfortable with this discussion, I'll be glad to stop by with an SSR in my hand to show you ..

I'll do some digging to find my SSR and compare the specs to the one you selected. I think we used a much smaller input current, but of course you want about 25 amps output side to have some headroom on the max loads you can connect.

**Jack Stevens** · 11-14-2016, 03:23 PM

Joel -

I'm between tickets to work for my job right now, saw this, and I'll post what @Don Williams (http://LakeMyraChristmas.com) would say.

Use two C9 incandescent bulbs (must be incandescent, not LED) on the channel as spike snubbers.

He says one will work, but the second is there "just in case" the first one burns out and you don't catch it.

What kills the controllers when turning on/off motors is that inductive kick the coils in the motors generate when starting and stopping. A C9 bulb is enough of a load resistance to suppress (snub) that inductive kick. Put it as close to the load as practical.

I know Al In Raleigh did his Grinches this way; the blower motors on one channel, the internal lights on another.

**kidcole** · 11-14-2016, 03:33 PM

I'm on the safe and effective side of this debate. Once you make an SSR, you can use em for anything you want. A little extra effort goes a long way .. I am not a fan of snubbers, except for with LED strobes ..

**rcktpwrd** · 11-14-2016, 04:45 PM

@Jack Stevens thanks for the info about snubbers!

@kidcole thanks for the wiring layout, it make sense to me now. This style of relay is just inline on the hot wire.

I'm not going to use this in our display until next year, so there is plenty of time to sort it out. But you have to ask the questions while thinking about things!

**kidcole** · 11-14-2016, 05:47 PM

Originally Posted by rcktpwrd

@Jack Stevens thanks for the info about snubbers!

@kidcole thanks for the wiring layout, it make sense to me now. This style of relay is just inline on the hot wire.

I'm not going to use this in our display until next year, so there is plenty of time to sort it out. But you have to ask the questions while thinking about things!

Absolutely .. Always good to plan ahead.

I used a couple SSRs for blowups until I sold a couple of my blowups. The guy was really interested in the SSRs so I sold them with the blowups. I bought more parts to make a couple more but by then I was just plugging them all in before I started the sequencing. I just left them on all the time. But it would have made things a lot better to have been using them. If I was not going to be home when the show started, I had to plug in all the blowups before I left. Sometimes many hours. SSRs are handy to have around ..