thermocouple and multi meter

Awesome bit of work putting this all together... any chance of making it into a tutorial (and sticky)?

Cheers,
 
I know this is an older thread but it is filled with great info. Thanks to all who contributed. Stacy is the man!!!

I do have one thing I have not been able to figure out. The fan speed controls. I know you can use a rheostat or a pot but which ones? Can someone point me in the right direction or make it real easy with a link?

Thanks again.

Seth
 
It is good to see this pop back up. I get an email at least weekly from someone wanting info about this subject.

I have temporarily stored the boxes of parts for "The Ultimate Controller" , "The Automatic Reciprocating Hydraulic Press", and the "World's Most Over-engineered HT Forge" until I get the new shop built. Those and several other projects will be then written up as tutorials, and possibly complete "Built-it" booklets.

Things are returning to normal, and I hopefully will lay the slab in a couple months.
 
Seth,
Sorry I haven't had time to answer your email.
If you use a small motor speed controller, like the ones at HF, you should be able to slow down that squirrel cage blower. I just use the inexpensive blower controllers available on ebay for about $5. Some motors control better than others. AC/DC motors control the well, with brushed DC motors being the best.
 
I really hate being this ignorant and I promise I am not usually a total imbisile but I have no idea what to even search for on Ebay or at HF. The search terms BLOWER CONTROLLER or MOTOR CONTROLLER seem to return nothing that could be of use.

Sorry for asking so many questions and taking up so much of your time when you are trying to be helpful.


Seth
 
Stacy,

What are you using for a blower?
Do you have a wiring diagram?

I'm interested in building a propane powered heat treat oven that is temp controlled. Your information in this thread is awsome. Thanks for taking the time to type it all up.
 
Schematic and explanation were in post 36 and 37. I have several blowers. The DC blowers are the best. Any motor with brushes is fully controllable.
 
Stacy
I did not see in this thread how one can use a SSR to turn on/off 220VAC.
Most of the SSR's at Auberns website are for 120vac. I plan to use two of these to switch 220v for my heat treating oven. Is there a better way??
Chris
 
Either use a 220VAC SSR or do as most do...use two 120VAC SSR controls. Just run the control voltge (usually 10-24VDC) to both from the PID output.
 
Stacy
I appreciate the advice, I went ahead and ordered another SSR and plan now to use two to turn on/off my 220v heat treating oven with my PID. I hope the current/voltage from the PID can easily latch two SSR, but we will see. If not I will have the PID energize a relay and have that latch the two SSR's. I am leaning towards the relay at this time so I can have it energize the two SSR's and also potentially a 12v fan at the same time to keep the SSR's cool. I will post some pics when completed so others can see.
 
mount the SSRs on a big sheet of aluminum with some thermally conductive grease (the stuff they use for computer chips)
aluminum is almost as good as copper for heat dispersion

-Page
 
You want the cooling fan running at all times, not just when the SSRs are energized.
Pages suggestion is good, and cheaper than finned heat sinks.

Be aware that the current rating of an SSR is with a heat sink. It is about 1/3 of the rating without one.
 
I bought the cooling fins with it but I do think just mounting it to aluminum might be smarter. I have some 1" x 3" aluminum sitting around somewhere that should work well. I concur the fan running all the time would be much smarter. Glad I have you guys here to keep me straight. After the holidays I will post some pics when its finished.
CW
 
You want thermal conductivity and surface area to dissipate the heat from your heat sink, that is why purchased heat sinks and air cooled engines have fins. I suggested the aluminum sheet as an alternative to expensive heat sinks.
-Page
 
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