Author Topic: 2 pole, 2 way switch question  (Read 868 times)

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Offline Chris Wilson

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2 pole, 2 way switch question
« on: November 04, 2015, 11:28:02 PM »
I have 2 server power supplies, 50V at 73 amps each. Outputs are isolated from ground. I want to put them in a cabinet and have a high capacity switch to change their outputs from parallel to series. I want to use a 2 pole, 2 way switch for this, but suitable amperage ones are hard to find. The schematic I will work from is attached. Can I use this Ebay sourced switch, or even cheaper, use two double pole 100 amp mains isolation switches bought separately (for a lot less) with their toggles bridged together and mounted on a common DIN rail, with (and I think I would need to do this...) one mounted upside down??

http://www.ebay.ie/itm/CHANGEOVER-SWITCH-GENERATOR-TRANSFER-125-AMP-1-SINGLE-PHASE-DIN-RAIL-COSDIN-/281692272367?hash=item41962af6ef:g:0HwAAOSw9N1Vk9GR


Thanks!
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                 Chris Wilson.
 

Offline Ian.M

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Re: 2 pole, 2 way switch question
« Reply #1 on: November 04, 2015, 11:51:56 PM »
No.  Its contacts almost certainly aren't designed to clear a 50VDC high current arc.

You need a switch  rated for at least 120V 100A DC  (120V because it has to clear the arc when the PSUs are in series)

Try googling: 100A DC knife switch DPDT
 

Offline Chris Wilson

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Re: 2 pole, 2 way switch question
« Reply #2 on: November 05, 2015, 12:03:49 AM »
Ahh, OK, thanks, but would it be OK if no live switching was done? I cannot foresee a time when i would want to go from series to parallel or vice versa with the supply feeding a load.
Best regards,

                 Chris Wilson.
 

Offline Ian.M

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Re: 2 pole, 2 way switch question
« Reply #3 on: November 05, 2015, 12:40:12 AM »
Not OK, but it can carry the current and withstand the voltage.   If you are lucky, it might even survive operating under moderate load a few times.   However its an electrical fire waiting to happen unless you can rig an interlocked cover that shuts down the PSUs before anyone can access the switch.
 

Offline Chris Wilson

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Re: 2 pole, 2 way switch question
« Reply #4 on: November 05, 2015, 12:58:46 AM »
OK, got you, thanks for the warning, I'll probably look for a knife switch, but only I will be operating it, and all the big knife switches seem to be in China, much appreciated Ian!

Actually they do an enclosed one, I could put a microswitch on the cover and have it run a relay on the input side, I have some BIG relays... Cheers.
Best regards,

                 Chris Wilson.
 


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