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dan pfanenstiel

Electric heat treating oven

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Hey all, anyone an electrical type here?

 

O.k. I've searched and searched, found many references for putting together a 110v oven, and even a couple of references to 240v units. None using a digital controller.

 

I've not been able to find anything on wiring up a 240v oven with a digital PID controller running a solid state relay. Just seems to me that having two legs off the power supply, each with it's own 110v would need a bit different wiring than the 110v variety. I understand that the SSR is a switch controlled by the PID, so it disconnects power to one side of the element wire, but since both legs of the supply carry current doesn't that mean there would still be 110v up the other side?

 

Here's a pic. Turning eyes up at my ignorance would be appropriate now. :-)

 

mywiring.jpg

Edited by dan pfanenstiel

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Hi Dan, the drawing you provided shows the PID controller wired directly to the heat elements, when using a relay, the switched line of the PID controller is wired to the electro magnet (center) of the relay. Then both sides of the 240 volt are switched thru the relay to the heat elements.......there is no high amperage voltage going thru the PID controller. To get 110 volts to the controller, you just use a jumper off one side of the relay, and the common for the 240 volt. When I purchased any PID controller, the wiring diagram was provided, showing both types of installation, with or without using a relay. You might want to checkout Omega Engineering Inc., they are very helpfull with this kind of stuff, good luck.

 

 

 

Peter

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ahhhh... that makes it all come clear now.

:wacko:

:lol:

 

ive been meaning to put together a little oven .. i have the pid controller, elements and ssr ... and still get lost :rolleyes:

and so they just end up gathering dust in the corner.

 

stupid electrominical stuffs .. <_<

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Do you have the pin-out to the temperature controller and the relay - that would help a lot. If not - do you have the temperature controller description? I can search for the controller and help with the wiring. Also, what configuration are the elements (WYE or DELTA)? You will also need a thermocouple.

 

I would also suggest a cheap excess temperature controller to shut down the elements in case of a thermocouple break.

 

Scott

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I'm with ya there, Dee. Stupid wires.

 

Thanks Peter, I've got diagrams with the controller but they never show the 240v supply and where it goes. Or maybe they do, and I'm missing something.

 

Scott. Got the PID and SSR from Auber. Here's the ones.

 

Auber PID

 

Auber SSR

 

I'm basically following these directions, Oven tutorial, but he's used an analog controller rather than the PID/SSR set-up.

 

I've got the Kanthal wires, two of em, to wire in series for the 240v set-up.

 

My supply is a three wire, 30amp 240v dryer plug. I'm told it just has the two 110v legs and a ground.

 

It occured to me that adding another SSR to the second power leg and wiring to the same terminals on the PID might solve things. Might blow up too, with my luck.

 

Only other thing not in my diagram was a kill switch for the door, kills power to the elements while door is open but figured that was dressing on the cake.

 

Dan

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I'm with ya there, Dee. Stupid wires.

 

Thanks Peter, I've got diagrams with the controller but they never show the 240v supply and where it goes. Or maybe they do, and I'm missing something.

 

Scott. Got the PID and SSR from Auber. Here's the ones.

 

Auber PID

 

Auber SSR

 

I'm basically following these directions, Oven tutorial, but he's used an analog controller rather than the PID/SSR set-up.

 

I've got the Kanthal wires, two of em, to wire in series for the 240v set-up.

 

My supply is a three wire, 30amp 240v dryer plug. I'm told it just has the two 110v legs and a ground.

 

It occured to me that adding another SSR to the second power leg and wiring to the same terminals on the PID might solve things. Might blow up too, with my luck.

 

Only other thing not in my diagram was a kill switch for the door, kills power to the elements while door is open but figured that was dressing on the cake.

 

Dan

 

 

 

Hi Dan, the controller in the picture will control the relay, the 110v to power the controller is taken off one side of the 220v before the relay(otherwise no power), the 220v goes thru the relay when the controller calls for it, it'll energize the low voltage electromagnet slamming the contacts and completing the curcuit. The thermocoupler is totally seperate from the power in and out, and has its own wiring terminals(red is negative on thermocouplers). A quick call to the manufacturer about 220v and a relay will solve alot of mystery in this situation. Hope this helps :mellow:

 

 

Peter

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If you are going to use a solid state relay for this, you either need a two pole SSR, or two single pole SSR's wired parallel, one to each leg of the 240VAC

 

Most modern controllers default to the OFF state if the thermocouple fails in operation.

 

The thermocouple has a pair of terminals that are for it only. The power supply for the controller comes from one side of the line (120VAC) and the power to the heating coils is a separate supply wire that feeds into the SSR in side, heaters on the out side. You will need to make sure that your signal output of the controller and the SSR you use are the same (some are DC pulse, some are AC). It is simpler in some ways with all electromagnetic relays, but they do not have the lifespan, or short cycle time capabilities of the SSR technology.

 

I have thought about trying to build a wiring diagram tutorial for the set up on one of these, but never done anything about it.

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So, Mr Clark, what would it take to get you to do up that tutorial?

:D

 

if i beg and plead, would you take pity on me and the other electriomologically challenged?

:huh:

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Aha! So my inclination to add another SSR to the other leg wasn't bad. Amazing what I can do if I think about it hard enough. In the wiring I came up with, I just couldn't get past the fact that one leg from the supply would always be hooked up to the element wires somehow, giving it constant 110v. I also knew the controller wouldn't disconnect power if wired hot into the circuit, cause it doesn't handle the amperage.

 

Ya, the output for the SSR('s) is DC. Place I purchased the PID listed it as for SSR output control rather than relay output, so all's good there.

 

So if one would use two SSR's in series, one would jumper wire the two SSR's together? Oh heck, here's a pic.

 

mywiring2.jpg

 

So now would I need to run a separate 110v line to power the controller, or can I somehow pull off of one leg of the 240v? Don't see how, as there's no common lead. I can see having the two separate lines in, 240v for elements and 110v for controller but would rather it was all in one.

 

Thanks all for the help

 

Dan

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Whoa! Just realized that last picture was wrong. One lead from PID is neg, the other pos, so the wires to the SSR's are wrong.

 

Hope nobody is using these examples as correct. These are my mistakes waiting to be corrected.

 

Dan

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Hokay, after much digging around the net and finding little (I'd rather search for a TTT diagram for rubber tires), here's my latest wiring rendition.

 

mywiring2.jpg

 

Does this look right?

 

After Howards post there I went ahead and ordered another SSR. Now the building.

 

Dan

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That looks much better - but I am not sure why you have two SSRs - seems that one would work. Perhaps I don't understand the element wiring.

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Dan the only problem there is the control or signal wires from the controller to the two SSR's should be parallel, not series. The rest of it looks ok in the last one. :)

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Ah good. Makes more sense now. Knew I shoulda taken electronics in school, instead of semester after semester of metal class.

 

Scott, the two SSR's are to allow the controller to kill both legs of the 240v supply power to the element wires. Since the element wire is basically a loop, if the power is still hot to one side it's still getting 110v without the relay switch. Adding the switch kills all voltage the the element wires when the controller kills the SSR's. Dunno if it's specific to my conditions, but because i don't have a common wire in my supply, a four wire arrangement, my 240v supplies power to the heater elements and I'll have to run a standard cord to an outlet to power the controller (I guess).

 

Updated picture.

 

mywiring2.jpg

 

Love it when i get to build stuff and learn too.

 

Thanks all

 

Dan

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Thanks Howard.

 

BTW all, after searching around a bit for a two pole, single throw SSR for this, I did end up ordering another single SSR from Auber. But, after ordering I did find the two pole one at Omega, so it is available. Just in case anyone is following all this.

 

Dan

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