A.T.S. Automatic Transfer Switch
- Thread starter Young Frankenstein
- Start date
MeuserReef
Welcome to the next level
You are the man. The ATS is the last piece to my "Maga Backup" that I have been working on.
MeuserReef
Welcome to the next level
What is the 120V DC part. Im guessing the battery?
Siffy
New member
You have a relay model to recommend? And where to purchase online?
Would these work with a transformer to supply wall power? They're only 25amp, not the 50amp you recommended, but can relays be run in parallel?
http://surpluscenter.com/item.asp?UID=2007080517464253&item=11-2420&catname=electric
Would these work with a transformer to supply wall power? They're only 25amp, not the 50amp you recommended, but can relays be run in parallel?
http://surpluscenter.com/item.asp?UID=2007080517464253&item=11-2420&catname=electric
Young Frankenstein
New member
Thats a typo is 12VDC
MeuserReef
Welcome to the next level
OK figured so. Thanks.
Young Frankenstein
New member
The relay has to be rated for at least 50 Amps. There's a some more complicated way of doing this with 2 relays an AC and a DC relay this would be probably cheaper for parts, but is more work and will put an extra burden on the DC battery, so I wont recommend it but I will post a diagram of it probably tomorrow. now let me find a cheap relay for you DIYselfers.
Young Frankenstein
New member
I would go with something like these.
http://www.grainger.com/Grainger/items/6X563 $24.00
but if you search you can probably find something within the $ 10.00 range. Or parallel 2x25 Amps relays.
http://www.grainger.com/Grainger/items/6X563 $24.00
but if you search you can probably find something within the $ 10.00 range. Or parallel 2x25 Amps relays.
Young Frankenstein
New member
Another happy customer, ladies and gentleman
you welcome 
MeuserReef
Welcome to the next level
Ahhh.. Beautiful. I have a Grainger account at work = Free shipping
stugray
Premium Member
Are the pumps you are driving here connected to AC when the power is on, or are they dedicated pumps that run only when the AC power is off?
If they are connected to the grid for AC power normally, then when you close the relay to drive the pumps, you will be backdriving the grid with your UPS.
I think you need another relay, or extra poles on the one relay to disconnect the pumps/accessories from the grid when the relay is transferred.
If you finish the drawing from the left side to the pumps & include the regular AC power n the diagram you should see what I mean.
Am I missing something?
Stu
If they are connected to the grid for AC power normally, then when you close the relay to drive the pumps, you will be backdriving the grid with your UPS.
I think you need another relay, or extra poles on the one relay to disconnect the pumps/accessories from the grid when the relay is transferred.
If you finish the drawing from the left side to the pumps & include the regular AC power n the diagram you should see what I mean.
Am I missing something?
Stu
Siffy
New member
I was thinking similar the same thing as stugray. Except I'm wondering if back driving an inverter can cause damage to it.
If you rewire the relay circuit a bit, both problems could be solved. Only bad thing is you'd be driving the inverter 24/7. But you'd also get by with using a lower amp relay. I'll see about drawing a circuit to better explain what I mean.
OT: What program do you use to draw circuits 0 Agios?
If you rewire the relay circuit a bit, both problems could be solved. Only bad thing is you'd be driving the inverter 24/7. But you'd also get by with using a lower amp relay. I'll see about drawing a circuit to better explain what I mean.
OT: What program do you use to draw circuits 0 Agios?
miwoodar
Likey the bikey
http://www.allelectronics.com/cgi-bin/item/4PRLY-120L/search/120VAC,_4PDT_KH_RELAY_W__LED_.html
I used one of these...I'm only running ~50 watts at 120 volts through it though.
I used one of these...I'm only running ~50 watts at 120 volts through it though.
Young Frankenstein
New member
Ohms Law
50 watts / 12 volts = 4.1 Amps
You are safe, and just use a 5 Amp fuse at the output
For those that don't know ohms law ......... I don't think you should be building this project.
Young Frankenstein
New member
That diagram is totally wrong. I will explain later.<a href=showthread.php?s=&postid=10489729#post10489729 target=_blank>Originally posted</a> by Siffy
Is this safe? Sharing the Neutral. If not, wiring it to a DPST relay would be possible.
now I am going to work .....
lakee911
New member
You can't parallel relays to increase the contact amperage. Unless it's specifically designed for paralleling, you'll get one closing a split second faster and cause arcing with extra high load. This can damage the contacts (increases resistance) and eventually cause a fire.
Someone suggested a contactor and that's what should be used. It needs to be rated for load breaking.
Don't share a nuetral. Completely isolate your system from the utility.
Siffy
New member
<a href=showthread.php?s=&postid=10490311#post10490311 target=_blank>Originally posted</a> by 0 Agios
That diagram is totally wrong. I will explain later.
I'd like to have a way to use the same pumps under primary and backup power. Just to keep from having extra "unused" powerheads in the tank. Not only for looks, but a PH just sitting in a tank almost never running likely won't start when you need it most. I'm thinking about algae.
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