SSR Heater Circuit for 3D Printer Heated Build Plate

Discussion in 'The Projects Forum' started by danl, Jun 26, 2015.

  1. danl

    Thread Starter Member

    Sep 24, 2013
    Please take a look at this circuit and design for heating a build plate on a 3D printer.
    The large size (18x18") of this plate makes it kind of unique so there isn't a ton of info in the 3D forums on higher wattage plates.
    The SSR planned for use is an OPTO22, 240Di25, $35. 240VAC, 25A. (supposedly made in USA)
    The plate will be heated by an 18x17" silicone heater, 120VAC, 1200W (3.9W/sq in).
    I've read that cheaper SSR's $8-15 range), especially the EBay and Amazon stuff, have high failure rates.
    The Opto22 line seems to be a good trade off between affordability and quality, vs the high end SSR,s.
    Any comments on the project very much appreciated.
    Dan heater web A.jpg heater webb.jpg
  2. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
    Looks good so far. You have both the line and neutral connections the same color and unlabeled, so here is some advice. Line goes to the fuse first, then the ssr, then the cutout, then the heater. Neutral goes to the heater.

  3. danl

    Thread Starter Member

    Sep 24, 2013
    A Kid...thank you very much.
    Attached shows your suggested changes.
    heater webb.jpg