I was given a Ceramics Kiln that is designed for 208V and I am trying to see if there is a way I can run it at 240V. It has 6 elements made of 16AWG Kanthal APM resistance heating wire. Each element having a resistance of 26 ohms. Elements are wired in parallel pairs.
I tried changing the element pairs to run in series to reduce the voltage across each element to 120V. This worked; but, the power reduction was too much and the kiln only got to 1100F. Goal is at last Cone O4 (1945F) with stretch goal to Cone 6 (2232F).
My next thought is to try running the some of the elements at 240V. This would be 9.2A compared to the 8A at 208V; but, I would really like to know if the wire can safely handle the 9.2A before I risk damaging the element wires.
How to figure the max current capacity for different gauges of Kanthal wire. I have been looking for a while and I can't find anything.
Update: I ran a test with some of the elements at 240V and they did not fail; but, presently I am testing using a 30A circuit so I can't run more than 3 elements. I have to move the kiln to a different location to test with 50V (which would allow me to run up to 5 elements. This empirical test is nice; but, I would like to have some analysis to know how much margin I have.