Why the SSR?

Discussion in 'Getting Started' started by Andy Cohen, Sep 5, 2019.

  1. Andy Cohen

    Andy Cohen Well-Known Member

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    I ordered it, but I do not understand it's advantage. Anybody?
     
  2. blarbles

    blarbles Well-Known Member

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    SSR provides direct AC power to the bed rather than relying on the Duet to provide power. For the US version of E3D high temp bed:

    "These are wall powered (120V) heated beds to be used for printing high temperature plastics or where fast heat-up times are required. They must be used with an SSR to switch and control, due to using main voltage (wall outlet power)."

    If you used a different bed that maxed out at 90-100c and did not run off 120V you could skip the SSR.
     
  3. Andy Cohen

    Andy Cohen Well-Known Member

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    I bought their HB and it's for US 120v so I guess I use it. So rather then the power for the HB coming from the Duet board it comes from the PS via this SSR which is controlled by the board?
    Wait... ! What? I admit I was NOT paying attention!! t
    The HBP is 120V?! Wow! That thing is gonna get up to heat FAST! Anybody out there using this yet???
     
    #3 Andy Cohen, Sep 5, 2019
    Last edited: Sep 5, 2019
  4. blarbles

    blarbles Well-Known Member

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    You are piggy backing on the power supply's incoming mains. The PS isn't providing any power to the bed. This allows you to have 1 switch for the whole printer. Your Duet is telling the SSR when to switch on/off.

    I am using the 120V bed. I've been calibrating with PLA so I've really only put it up to 60c, but it gets there extremely fast.
     
  5. Spoon Unit

    Spoon Unit Well-Known Member

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    Yep. It's crazy fast to heat up. 80C is around 2 mins and I think 105C is under 5 mins.

    Once the bed reaches heat you'll see the red light flashing power on and off to the bed. As @blarbles says, not actually power to the bed, but power to the SSR. The SSR has a little yellow light on it that you'll see also flashing. That's the gate to mains power.

    In the UK, this means we're pushing 240V into the bed.
     

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