Wednesday, June 10, 2009

Element Design --- Our Final Idea --- Part 4

Well those elements are ordered and we now just have to wait for them to come. I sent the controller box down to Terry so he could install the Solid State Relays. These relays cycle on and off every 200 milliseconds so the elements do not get that much hotter than the kiln.

Here is what we decided to do. There are 8 elements in all in the kiln, three in each side section and two in the floor. We divided up the kiln into 4 sections of 2 elements each. This is quite different from how the kiln was originally wired, which was a 3, 3, 2 configuration.

Each of these pairs of elements will be wired in series within the pair, and all 4 pairs will be wired in parallel to each other. The elements will be 8 ohms each so each section will be have 16 ohms of resistance and 15 amps of current, and all 4 sections will generate 60 amps.

The wire is going to be 12 gauge Kanthal A1 wound around a 3/8 inch mandrel. This gives us a very good length to the element -- when it is stretched the pitch is just about perfect. And the watt loading figure is very low so these guys should last a long time.

Let me know if I need to be more specific about any of this -- how we did it, why we did particular things.......



Dan Finnegan said...

John, Even though the math makes my brain shut down I have enjoyed your element discussion. My electrician friend Bill is really enjoying it. He long ago convinced me that my L & L kiln was far superior to the others and even enjoys reading the manual. Is the search for the perfect element driven by economics, efficiency, or a specific need of control for the work you make?

Alex Solla said...

I guess my comment is along the line of Dan's this morning.

Where do/es current elements/element design fail in your needs?

Did your needs change after buying the kiln?

Is this an ideal element for just your firing process in general or a holy grail element design?

Thanks again for all of your help with my thermocouples. It was wicked depressing seeing all those metal filings come pouring out of the protection tubes.