I spent the last two evenings putting together the PID controller box for the forge. Master switch is on the side of the box closest to the forge. As I mentioned before, the burner will be a two-stage setup with PID controller allowing temperature control without losing ignition. It's Stacy Apelt's design, and the low burn will sustain ignition and hold to a low set-point, and the high stage kicks in to bring the forge back up to a high set-point temp after falling too far. Just to make this thread a one-stop-shop, here are the links with discussions and WIP's of JT's forge.
I used the schematic JT put together from Stacy's original sketch as a basis for my wiring. Being a visual person, I had to go ahead and draw it out myself using colors that corresponded with the actual colors of the power cords I was using . Here's what I came up with:
As Stacy reminded me, I did add a 2Amp fuse just after the main switch as well as a 1Amp fuse just before the PID.
Here's the parts I started with:
And following the above schematics, I came up with this:
Notice the cords are all protected that run around the forge just in case. I'll also add some sort of sheild for the SSR (on the outside of the controller mounted to the metal plate to act as a heat sink). I tested it out, and it works...with some quirks. Turns out I wired up the speed controller backwards (no labels on the controllers as to the in vs. out). So when I first tried it out, the blower was blowing full blast at the lowest speed setting. In fact, no matter what direction I turned the knob, the fan trucked along just fine. Turns out there is also a min-speed pot on the controller that I had to adjust to set the min speed. Now, with the knob turned all the way to the right, the fan is running nice and slow, and with the controller turned all the way to the left, it runs full tilt. Note the high and low controllers so that the forge atmosphere can be controlled in both high and low settings.
There will be more to come as far as the gas side of things when I get to setting up the two-stage gas controls. It's basically a needle valves to control atmosphere for each stage along with a solenoid on one stage that opens with currnet from the controller to turn on the high stage.