I found the signal ON from the PID to the SSR was enough to drive the above fan but only for a bit. The PID would reset/shut down. The fan in the case I used (that pulls more current) put the PID in an immediate constant cycle. I knew I needed to run the fan off a transformer.
The box I had from a server power supply had all the stuff I wanted:
- Place to mount all the guts
- Cooling fan
- Main power switch with leads
- Receptacle for removable power cord
I needed the Fluke to find the +/- DC output from the 1250 mA transformer to wire the fan properly (so it would blow outward not inward). The fan in the box is a .250A <250mA> fan....the transformer rated at 1.25A <1250mA>. Here's a picture of the first live test using a soldering iron as the load (instead of the casting pot).
.....so......
I found my DC hot and ground off the transformer and rigged the real fan that came in the box (I wanted to use it and the not spares because this was a better fan than the other two and one of the others had three wires ~?~)
Now all functions test A+ so it's time to make all this crap fit in a small metal box, rewire permanent like with reliability, then make sure it fits and works, then make sure it fits and works, then make sure it fits and works.
Here I've cut the hole in the metal panel. To plan its location I had to loosely orient the parts in the box in a way that made sense. This was the most difficult part because not only did all the stuff have to fit, but it had to be "assemble-able" meaning access to all the lugs was important.
Here's a test fit pic where I'm making some of the permanent leads as short as possible but still long enough to get it together and apart. All connections soldered (other than the ground I added from the outlet box to the main case ground that was already there <I piggy backed it by adding another but on top of my crimped and soldered ring>).....
I didn't use a bus bar because I didn't have one. I have $3.92 in this so far. No need to make it cost EVEN MORE! There's no need. There are too many connections to NOT be able to find a couple places to double up. You can see my solder (done with a torch of course), heat shrink (done with a torch of course), and checkered Vans...LOL.
PID up top lounging in its new hole....in the bottom case you have the SSR mounted on a heat sink with special grease in between mounted right in front of the exhaust fan. To the right you'll see the transformer. It had too many mounting issues.
- No mounting holes
- Robbed from an adapter encased in plastic where it was double side tape stuck
- Flimsy circuit board attached
- Circuit board coundn't be allowed to ground to case
Here's a closer look at the SSR, transformer, and fan. The lid is kinda making it an odd picture to look at but I wanted the leads as short as possible to the PID (mounted in the lid)...<rhymes> So it makes it hard to get the lid outta the way for pics, see?
Box assembled with shorter leads....except the ones that go to my regulated outlet. THIS IS WHERE THE $3.92 COMES IN. I had the outlet but not the box, the cover, or the machine screws and nuts I needed to stick it all together. At this point all that's left is wiring the outlet, making and installing the ground from the added box to the main box, and trying to figure out translated Chinese.
IT WORKS! Well, it lights up and turns on stuff. I had to play with a bit and finally got the set temp set. Also ran a couple automated learns. It got more consistent when I changed the target temp to 685 and reran the AL. Then I moved it back to 700 and it then ran 698-703.
I still have to make a bracket to better support and aim the temperature probe....keep it off the sides and bottom as well as outta my way!
More pics...
YUMMY! I don't know which was more mentally challenging....figuring all that crap out and doing it in one day or trying to describe it THE SAME DAY WITH PICS?
The only other change will be to the transformer wiring. The way I designed it in my head was for the fan to only run when the PID demanded the SSR to "close". Oh my....the sneaking up and down of the PID as to temp coupled with a loud fan doesn't help casting Karma. I'll take the hot lead off switch by PID and move it to the 110 VAC lug off the main switch and just have it make a constant hmmmmmmmm.....
