PID wiring question

[Sasquatch-1]

Is there a way to pull a constant 12 volts from the PID circuit to run a cooling fan?

[HATCH]

not really.

Your PID typically runs on 120V
The output that powers the SSR is typically about 8 volts @40ma

You could purchase a cheap 12v power supply for around $13 from amazon. link
Just hook the input power up to your on/off switch

[JonB_in_Glencoe]

12 volts DC?
I am 99% sure than 99% of the cheap ebay PID's will not have 12vdc ...and if they do, I don't think they'll power a fan.

First you shouldn't need a fan, but if you gotta have one, there are 120vac to 12vdc power converters for sale on ebay or other places. Also, if you have a stash (like I do) of the Plug-in type transformers that many items use, look for one that is 12vdc

[Sasquatch-1]

Thanks for the response. I have old wall adapters just wanted to know for sure that there isn't a 12 volt out. The main reason for asking is I have an old computer power supply box (already gutted) that has a fan mounted on the outside and thought it would be nice to have the additional cooling.

[HATCH]

In our application you won't need the extra cooling.
Typically most people run 25 amp Solid State Relays (SSR)
The Lee 4/20 pot has a 700 watt heating element. So that is around 6 amps (a little less to be exact)
The SSR shouldn't get hot. It may get warm to the touch but not hot enough that you can't keep your finger on it.
I have installed SSR with no heat sink on plastic enclosures with NO issues whatsoever.

[JonB_in_Glencoe]

old computer power supply box

one of my future projects is a second PID. I got a burnt out computer supply from my SIL, just for the box ...I plan to remove the fan. It's a metal box and mounting the SSR to that will provide more cooling than needed. the first PID I built, the SSR doesn't even get warm.

[jim147]

They do make small 120v case fans. You can get them from Amazon or Microcenter.

But as the others said I don't think you will need it. I'm using one for a 3/4 HP walk in cooler. It is mounted outside by the compressor in a black box without a heatsink. It's been running six or seven years.

[bangerjim]

I use 120 vac mufin fans on all my electroinc, music production, and video equipment. Very easy to just plug it into an outlet or wire to your equipment. Most of my equipment has switched 120 vac outlets on the back.

I sell high end PID control systems and only a very few of those EXPENSIVE units provide what is called "transmitter power"....24VDC at 200 MA. These little cheapo 1/16 (or smaller) DIN PID on/off controllers you all are using have nothing like that available that I have ever seen.

Just buy 120 VAC fans or some 12vdc wall wort transformers..........if you have 12 VDC fans already. Here is AZ, we need extra air cooling. I really do not think you in WV would really need it!

banger

[Stewbaby]

I’m in the ‘don’t need it’ category also as long as powering the Lee pot or oven or such in the <8 to 10 amp range.

In hot humid Mississippi

[Walter Laich]

I built one for my PC oven and one for my luber/sizer mostly to do it--already had built one for my casting pot.

fun project and it brings a smile to my face when I see them working.