Like a power strip in reverse.

Thread Starter

Tweedle123

Joined Sep 12, 2020
6
Hi all,

I have three 110 volt devices that can output 110 volts when they are acivated at random events. I want all three devices with their 110 volt output to activate/power a single 110 volt device. Like a power strip in reverse. Is there a product like a reverse power strip out there?

Thanks
 

scorbin1

Joined Dec 24, 2019
44
That could potentially be pretty dangerous. Will the source for each device be a single common source? If two different sources are used, one could be on the opposite phase as the other. If both are applied to the source simultaneously you are creating a line to line short of opposing phases. That's much worse than shorting to ground and could easily turn your device into a pyrotechnics show at best case. Worst case could be pretty catastrophic. That being said, there are small transfer switches that you could buy that I believe accommodate for this sort of thing.

One way to accomplish this, if you insist on the DIY route, would probably be with an isolation transformer on each source with secondaries in parallel, but I am still not sure this is the safest way to go either. Hopefully others will chime in with some advice.
 

CBTech_Joe

Joined Sep 9, 2020
39
As far as I know, nobody has constructed that particular hazard. Many questions to ask before jumping in to this.
Are the power feeds all coming from the same source?
The concern here is that any out of phase power applied could be catastrophic.
You can use a single feed to the device to be controlled through multiple relays to ensure that only one source can be applied at a time.

Edit: Post came in while typing. Didn't mean to repeat.
 

Tonyr1084

Joined Sep 24, 2015
5,211
Nobody makes such a device for fear of culpability for any harm, death or destruction that may very very easily occur.

Culpability: meaning "Responsible for any outcome, good or bad."

In my basement there are two different outlets. Each outlet has a hot, neutral and ground wire, and their colors are respectively Black, White and Green (or bare copper). If you were to take a meter and measure from either black to neutral you'll see 120 VAC. But if you measure from black to black you'll see 240 VAC. That's because the power (in US and some other locations) comes in as a split phase 240 VAC with center neutral. From either L1 or L2 to neutral is 120 VAC. But from L1 to L2 is 240 VAC. You have little chance of knowing which line (L1 or L2) a device is plugged into. And if you plug into two different lines you'll get the full 240 VAC.

Now, if you were to build such a device as you propose - there's a 50/50 chance you'll hook two plugs into it and get a disaster. If you plug three devices into it - you have a 66% chance of a spectacular and exciting afternoon. As they say in Germany, "Das Machin Spitzen Sparken. Nigh Gerfinger Polkin". In more sober terms - build it and it will explode.
 

Thread Starter

Tweedle123

Joined Sep 12, 2020
6
Thank you all for your responses.

All three 110 volt feeds are unrelated to each other and they are all seperate devices that are unrelated to each other.

I was hoping there was something out there that acted like an I/O board. That I could plug in multiple 110 outputs and it would turn on and output a single 110 output regardless of how many time the I/O board was told there was an input.

edit, unrelated too many times-multi tasking.
 

CBTech_Joe

Joined Sep 9, 2020
39
All three 110 volt feeds are unrelated to each other and they are all seperate devices that are unrelated to each other.

I was hoping there was something out there that acted like an I/O board. That I could plug in multiple 110 outputs and it would turn on and output a single 110 output regardless of how many time the I/O board was told there was an input.
This would be easy using a PLC to monitor the inputs and turn on the output based on the conditions.

You can also do this with 3 relays. One power feed to the N.O. contact of all 3 that will connect to your controlled load, and the output from each of the three devices to the coils on the relays. Running the neutral from each relay to the other two relays N.C. contacts will ensure that only one relay is engaged at any time. Does that make sense?
 

Thread Starter

Tweedle123

Joined Sep 12, 2020
6
If I am right it seems you want to activate a device using all three sources?
IOW, an AND function, if so, use each input to activate a relay, and series the N.O. contacts.
Max.
I think it may be more like an "or function" as I want any combination of the three devices to be able to activate the single device.
 

Thread Starter

Tweedle123

Joined Sep 12, 2020
6
This would be easy using a PLC to monitor the inputs and turn on the output based on the conditions.

You can also do this with 3 relays. One power feed to the N.O. contact of all 3 that will connect to your controlled load, and the output from each of the three devices to the coils on the relays. Running the neutral from each relay to the other two relays N.C. contacts will ensure that only one relay is engaged at any time. Does that make sense?
Thank you for your reply.

I had wondered if a PLC could do the job. I am a mechanical being "ushered" into the electro/mechanical. It will take me a while to track down the info and understand your relay design. I think if a PLC can do it, that may be a cleaner way for me to do it.
 

Thread Starter

Tweedle123

Joined Sep 12, 2020
6
I think what you want is if any of the 3 devices (output 120 V) turn on a third. Logic OR.

3 relays with 120V coils wired to each device gives you 3 isolated contacts. They can be wired in parallel, so that any one of the devices turns on the 4th device
Thank you. That sounds really promising.
 
I had wondered if a PLC could do the job. I am a mechanical being "ushered" into the electro/mechanical. It will take me a while to track down the info and understand your relay design. I think if a PLC can do it, that may be a cleaner way for me to do it.
If you have access to a PLC, then wire the three 120VAC outputs from the devices to 120VAC inputs on your PLC then the logic is simple. Three inputs in parallel to a single output. Your assigned output gets connected to the device you are trying to control.
 
DIN rail is an automation professional's erector set. Here
is a random video that I didn't even watch. The grey stuff is wiring duct. The lid pops off and the wires can exit nearly everywhere.
But you can build custom terminal strips etc.

Here https://www.asi-ez.com/ is a place where quantity rules.

Your at the conceptual stage right now. You will pay for something that is pretty and troubleshootable.

There are IEC power inlets and outlets: https://www.interpower.com/ic/IEC60320.html
 

Tonyr1084

Joined Sep 24, 2015
5,211
This is what I was thinking for a possible home made solution. Notice the CONTROLLED output is dependent on each of the three inputs. Any single input can switch a relay and provide 110VAC at the output. One, two or all three can be active and the output is going to be on.

This requires careful following of instructions as again, getting it wrong can be quite messy.
 

Thread Starter

Tweedle123

Joined Sep 12, 2020
6
This is what I was thinking for a possible home made solution. Notice the CONTROLLED output is dependent on each of the three inputs. Any single input can switch a relay and provide 110VAC at the output. One, two or all three can be active and the output is going to be on.

This requires careful following of instructions as again, getting it wrong can be quite messy.
If you have access to a PLC, then wire the three 120VAC outputs from the devices to 120VAC inputs on your PLC then the logic is simple. Three inputs in parallel to a single output. Your assigned output gets connected to the device you are trying to control.
DIN rail is an automation professional's erector set. Here
is a random video that I didn't even watch. The grey stuff is wiring duct. The lid pops off and the wires can exit nearly everywhere.
But you can build custom terminal strips etc.

Here https://www.asi-ez.com/ is a place where quantity rules.

Your at the conceptual stage right now. You will pay for something that is pretty and troubleshootable.

There are IEC power inlets and outlets: https://www.interpower.com/ic/IEC60320.html
All you peeps are great, the above and all who responded here. I think I am set. Thanks again!
 

scorbin1

Joined Dec 24, 2019
44
If you are looking to go the PLC route and budget is an issue, i highly recommend the Click series of PLCs from Automation Direct. We have been experimenting with them, actually have a few in full production, and they haven't skipped a beat. For under $200 you have everything you need and the software is free!
 
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