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Need Help in SCR/TRIAC Project

Discussion in 'General Electronics Discussion' started by MiZZi, Feb 8, 2015.

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  1. MiZZi

    MiZZi

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    Sep 14, 2014
    Hi! I was wondering how should I isolate my low power components from my SCR/TRIAC which controls high powered loads. We currently have a project which entails controlling high power loads using Triacs/SCRs; however, I am not sure on how do I isolate the microcontroller (which we should use in the project as the controller of the SCR/Triac) from the SCR/Triac. Is there an electronic device that is specially made for that isolation? Thanks!
     
  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    Yes - optocouplers. There are several types. If you give us more details of the type of control you want (firing angle control? Cycle-by-cycle control? SCR or triac? What type of load? What voltage?) we can make some more specific suggestions.
     
  3. MiZZi

    MiZZi

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    Sep 14, 2014
    thanks for your reply. Hmmmm, Optocoupler. I'll definitely check that one. I'd like to control the firing angle. I'm still not sure whether I am going to use an SCR or a Triac but I would be using a motor as a load. It will be operated @ 220 V. Well, what can you suggest? Thanks!
     
  4. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    If you want to control the firing angle, use an optocoupler WITHOUT zero crossing circuitry inside it. Your optocoupler will also need a high output voltage rating (350V or more) unless you use it to control some other circuitry that actually fires the SCR or triac. Start with a Google image search for schematics, choose the ones that look appropriate, and visit the pages. http://www.google.com/search?q=triac+optocoupler+circuit&tbm=isch
     
  5. MiZZi

    MiZZi

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    Sep 14, 2014
    This is too much to grasp right away. Hehehe! Anyways, thank so much Kris. I'll definitely update you with it. THanks!
     
  6. BobK

    BobK

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    Jan 5, 2010
    There are also triacs with built in optocouplers. And some Solid state relays are basically that.

    Bob
     
  7. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    That sounds interesting... can you suggest a part number for me to check out?
     
  8. BobK

    BobK

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    Jan 5, 2010
  9. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    Ah, I see what you mean. I thought these devices were designed to control larger triacs - at least, the ones with zero crossing circuitry in them are. I guess I assumed that because they're described as optcouplers with triac outputs, not triacs with optocoupler inputs! They're like an MOC3063 with a bigger triac. But sure, they can be used on their own for fairly low-power applications.
     
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