michinyon:
They are accustomed to being turned on and off 120 times a second, already.
I've probably misunderstood what "burst firing" is. I'll try to explain how I think: You want to rise the furnace temperature by 10. This will take you 3 minutes with full power, then off. This was burst firing to me. If you instead let the difference between actual furnace temp and the supposed temp regulate how much power the thyristors let through, you will have a decreased power supply when t(diff) decrease. I'm am not thinking of cycles in the AC supply, rather in terms of furnace temperature over minutes.
If you turns the thyristors to 100% supply, they will become warmer, but for a shorter time. If you truly regulate them proportional to t(diff), the elements will push furnace temperature up a little more gentle, because the amount of necessary thermal energy will be delivered during a longer period. After working with the kiln for some time now, I think there are margins to let it work under softer conditions. During heating at a rate of 3 centigrades/minute, the contactors goes on and off within minutes - that is from zero to 100% power on the elements. I would prefer continous load at say 50-80 percent.
When I see dev's illustrations, I realise that burst firing is something else than I percieved, and probably works well within the scope I think of.
I'm sorry if I didnt got the context of your discussions!