High Current Switching

Discussion in 'General Electronics Chat' started by manjunaths82, Apr 24, 2009.

  1. manjunaths82

    Thread Starter New Member

    Apr 23, 2009
    2
    0
    Hi,

    Please let me know how to design controller for switching 20A of current.

    I have the following solutions.
    using a Relay as a switching element,
    using a SSR as a switching element.

    But use of relay the life is a concern, since it is a mechanical part it can't be used.

    using the SSR is costlier solution for us.

    please let me know can we build a SSR ourselves so that we can reduce cost.

    share if u have any circuits for the same.

    Thanks in advance
    Manju
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    At what voltage should this 20A be switched?
    Is it AC or DC voltage?

    Greetings,
    Bertus
     
  3. manjunaths82

    Thread Starter New Member

    Apr 23, 2009
    2
    0
    Hello Bertus,

    it is at 24V and 48V both AC and DC.
    can we have the same controller for both inputs?

    minor modificaitions will do.

    Please guide me.

    Thanks
    Manju
     
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,694
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    Another question is how many of the devices do you need? If it's just a few, versus hundreds, then I would suggest that you just buy an SSR. SSR modules are not that expensive --just a few dollars. If you start a design from scratch and build it, you will probably have much more than that in just parts, not including time.

    John
     
  5. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Are DC SSR's available? The only ones I've used were based on triac's or scr's.
     
  6. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,694
    904
    DigiKey lists 8 pages of DC SSR's. The Crydan D1D20 is just one example. It is rated at 20A DC. Search term: solid state relay

    John

    Edit: I didn't check how many of the devices on the 8 pages were effectively duplicates or not stocked. I suspect quite a few of the devices would be eliminated if one took those two factors into consideration.
     
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