PID notes

[Mike W1]

Some while back I ordered a REX C100 on ebay for a spare. Long story short I got a Chinese knockoff instead of the Japanese one I ordered. Ebay straightened the deal out moneywise and I didn't have to return the other so I decided to test it out.

Knocked together a box and hooked things up with wire nuts and spare parts. Wanted to see if the parameters were similar or not and plugged my luber heater into the new cobble job.

The only real difference is on this "temp" setup I didn't use a heat sink on the SSR which is located on the bottom of the floor of the box with no vents cut into other than about the 1/8" gap on the front side. A little duct tape secures the bare bulb TC to the SSR and I was set to monitor the SSR temperature.

Let it control my luber heater for about 2 hours to see what happened. Ambient temperature of the room was 68.5°F and the highest the SSR ever got up to was 72.4° F. Not a lot of heat generated there as I'd already guessed might be the case.

I did have to run the Autotune twice and the then I controlled the temperature of the heater just fine.

Several days later I hooked the "new one" up to one of my lead pots and ran a fairly short casting session keeping an eye on the SSR temperature. Again I had to run the Autotune twice but it then controlled the pot temperature just fine.

I had stuff written down for my notes but must have neglected to save the file changes and they're long gone I guess. But I did heat the old shop up to around 87-88° F that day and memory tells me that the SSR didn't go over 5-6° F higher than ambient. Normally I'd not omit the heat sink but certainly for my purposes don't think a fan would be necessary for melting lead for bullets either.

Found my note file. Shop high was 88° F, SSR high was 92.3° F

[Stewbaby]

Good deal. I’ve omitted it from all of mine. When the SSR is just running a ~800 watt pot (<7 amps which is 1/3 the SSR rating) or even a toaster oven for powder coating, it just isn’t loaded enough to heat up much.

[jsizemore]

I've mounted my SSR's to my well ventilated cases without trouble. The one that operates my casting pots and the other that controls the toaster oven are from aluminum cased power supplies. Sure is nice having an outlet already cut into the case. The lubesizer PID is in a steel power supply case. Again, lots of ventilation. I've checked all the cases at the initial startup till first cycle and have only had the 6 degree rise with the thermocouple probe in the case hole next to the SSR. PID on the casting pot is set for 700, 400 on the toaster oven, and 92 on the lubesizer.

[Mal Paso]

The SSRs produce a little over one watt for every amp controlled and that’s only when active. The temp goes down as the pot temperature stabilizers. I had a huge copper core processor cooler on my first one just to use it for something. Now I bolt them to the case unless there is a free heat sink with the SSR.