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Old 11-22-2012, 09:52 PM   #1
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Contactor Question

I have a 240v50amp circuit (2h/g) and I want to control the line current to the outlet via a timer. Simple enough to do with a contactor and a 120v timer. The complicated part is that I actually want to control the line current to two different outlets and if I could design my own contactor, here is how I would describe it: 2 hots coming in on the line side, 4 hots on the load side (2 pairs of hots) and 2 timers where 1 timer determines when current flows through and the other determines which pair of hots on the load side is actually supplying electricity. Once the first timer goes off, one of the load pairs will always be supplying ... the second timer determines which one. I have no idea if this type of thing exists or a safe way to cobble some different pieces together to make it work. Any thoughts are appreciated.


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Old 11-22-2012, 10:24 PM   #2
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What you want to do is easy....

2 Basic ways to do it....

1. Using to Time Delay Relays
2. Pico PLC controller...

Me being the PLC guy I am would go for the pico many cases, it's cheaper than 2 TDR's.

While I hate Automation Direct....I doubt you want to pay for Allen here is an example of what would work for you...


Even if you are on the right track, you will still get run over if you just sit there.

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Old 11-22-2012, 10:27 PM   #3
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I'm thinking two contactors, with the contactors being alternately switched by the NO and NC contacts on timer # 2.
Timer # 1 feeds the common terminal on timer # 2.
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Old 11-23-2012, 04:12 PM   #4
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Use two timers with no & nc contacts, and four two pole contactors
the contactors are wired back to back
the first two contactors are controled by timer one,
one on n/o, the other on n/c.
this selects which feed is used.
outputs parrallelled and wired back to back with other two contactors
these other two are controled by timer 2
via n/o & n/c on timer.
This selects which load is feed.
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Old 12-11-2012, 11:33 PM   #5
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Thanks - this is exactly the type of thinking I was looking for! I took a look at the PLC bits and think I understand how it all comes together, but I'm having trouble understanding how the 75amp relay can handle a 4awg wire - it looks like a 12awg screw terminal. I said in the original post that it was a 50amp circuit (which it is) but will be upgrading the breaker and endpoint for 75-80amps. I thought maybe it was the picture, but the picture shows the appropriate model number etc. for the 75amp version. Am I missing something? Thanks again - this really is a very clean solution and at the cost of multiple contactors, most likely the cheapest way to go.
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automated switch , contactor , timer

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