- Joined
- Jun 17, 2011
- Messages
- 2,062
Last spring, while I was still out of my house after the fire, I made a trip with a buddy to pick up some equipment from an engineer/machinist who was closing down his shop. My main interest was the heat treating oven he had built. I couldn't get his controller to work so I ordered a PID unit from eBay. I had that working, but realized that I had the two elements connected in series. (Comes from the lag between ordering and receiving the PID) When I connected the elements in parallel (9.4 ohms - 25.5 amps @ 240 volts, over 6000 watts), the 40 amp solid state relay blew.
I finally got the oven running today. This week, I bought a 50 amp SSR at the local electronic supplier. It does a nice job, working with the PID.
The process of setting up the PID controller included making a large aluminum heat sink ...
The attached SSR is the one that blew.
I built an aluminum enclosure to fit.
Here's the oven mounted on the stand that used to carry my ZX-25 mill/drill. The small display is a thermocouple gauge that I was going to use for the oven I was building before the fire. It reads in Fahrenheit, while the controller reads in Celsius. I thought it would be useful to see both at once. Unfortunately, the small one reads a LOT higher than the controller. As the saying goes, "A man with a clock knows what time it is. A man with a hundred clocks is never quite sure." I'll have to find a way to calibrate the whole affair somehow.
I finally got the oven running today. This week, I bought a 50 amp SSR at the local electronic supplier. It does a nice job, working with the PID.
The process of setting up the PID controller included making a large aluminum heat sink ...
The attached SSR is the one that blew.
I built an aluminum enclosure to fit.
Here's the oven mounted on the stand that used to carry my ZX-25 mill/drill. The small display is a thermocouple gauge that I was going to use for the oven I was building before the fire. It reads in Fahrenheit, while the controller reads in Celsius. I thought it would be useful to see both at once. Unfortunately, the small one reads a LOT higher than the controller. As the saying goes, "A man with a clock knows what time it is. A man with a hundred clocks is never quite sure." I'll have to find a way to calibrate the whole affair somehow.
