Oven Element (240v) Questions

Discussion in 'Smoker Builds' started by solaryellow, Dec 27, 2009.

  1. solaryellow

    solaryellow Limited Mod Group Lead

    I have spent about 4 hours researching PIDs, relays and 240v. I don't think it has helped clear anything up for me so hopefully you can help.

    As usual, I want to be cheap so I have been looking at PIDs on ebay as well as some other websites. I have a box of 240v elements on its way to me for the great price of $0.00. I want to put one in my plywood smoker I built a few weeks back for sausage, jerky and cheese.

    I understand hooking up the PID to a relay, but that is where I am getting stuck. The relays I am seeing have a terminal for a single leg. Do I need two relays for both hot legs? Is there a special relay designed for 240V? Or do I wire one leg to the relay and wire the other directly and rely on the PID to cut off the second leg which would interrupt the 240v circuit?

    Any help would be appreciated!
     
  2. nickelmore

    nickelmore Smoking Fanatic

    There are DPST relays (double pole single throw) Think of relays as simple on off switch.

    Planing on using 240 to power your smoker?

    I have a 110V element hooked to a PID and cant seem to get it to stop cycling too fast.

    I am afraid that the fast cycles will shorten the life of the coil.

    There is a pretty good wiring diagram floating around for a Bradley.

    I was wondering how many watts a oven element was, if you run them at 115, it would be half of what they are rated.
     
  3. bud lite

    bud lite Smoke Blower SMF Premier Member

    If you run it at 115 volts (half), the current also drops to half.
    Since power (watts) equals volts times current, the power consumed will drop to 1/4.
    1/2 times 1/2 equals 1/4. [​IMG]
     
  4. beer-b-q

    beer-b-q Smoking Guru OTBS Member

  5. solaryellow

    solaryellow Limited Mod Group Lead

    I had looked at that but didn't like the price tag.
     
  6. solaryellow

    solaryellow Limited Mod Group Lead

    I was looking for some on Auber's website and didn't see any. I will have to look elsewhere.

    Yup. Already have it wired in the garage for a welder.
     
  7. mballi3011

    mballi3011 Smoking Guru OTBS Member SMF Premier Member

    Guys you are really going way over my head cause My shirt says commerical drywall on it not electrician.
     
  8. nickelmore

    nickelmore Smoking Fanatic

    I got my relay at Grainer, it is DPST 20 or 25 amps

    It was not cheap, I think about 20 bucks or so. In stock ordered it and it was at my local branch the next day.

    I am about as frugal, resourceful, and down right cheap as a guy can be, but you have to look at the whole project. I have a custom built smoker that uses propane or electric with a PID controller and probably have less than $150 into it. You can scrounge around but in the end time is time.

    I enjoy looking for stuff for projects but sometimes you just know you are not going to "find" what you really need.
     
  9. nickelmore

    nickelmore Smoking Fanatic

    Been a while since I had to use PIE,
     
  10. solaryellow

    solaryellow Limited Mod Group Lead

    I will post up exactly what I did when I get it all figured out and draw it out in crayon for us simple people. [​IMG]

    The only time constraint I have is my own patience. [​IMG]

    25a should be more than enough for me I would think. 240v x 25a = 6000w. I think I have a few buddies with accounts at Grainger. Although that 1200w fin heater at Grainger would make the element/relay issue disappear as I could use a PID with a 120v relay. That would be roughly $100 for all of that. Hmm...
     
  11. bbq engineer

    bbq engineer Master of the Pit OTBS Member SMF Premier Member

    Hey Solar Yellow,

    What you are looking for is a double pole relay or more commonly known as a contactor. They are used in HVAC systems, and hot tubs to control the power to the heating elements. Here is a pic of what you will want to do...no wise cracks because I drew it in Paint.


    Now I have the PID controlling the contactor in this diagram. What happens is that the PID (or external relay if you use one) makes the solenoid activate and make contact for both legs which supplies 220 VAC to the heating element on the right. Here is a link to a place I have used for my hot tub contactors. The price is right and they are name brand Siemens parts.
    http://cgi.ebay.com/Spa-HOT-TUB-CONT...item35a3990b6a


    You will also want a Normally open (N.O.) setup and pulse the power on to provide heat.

    Let me know if you have any other questions as I would be more than happy to help.
     
  12. nickelmore

    nickelmore Smoking Fanatic

    I like that finned element at grainger. Easy to protect, easy to put a fan in front to circulate heat.

    I am still having minor issues with my PID, I think it cycles more than I would like it to. I friend of mine says that I need to circulate air over the coil to make it "work" harder so the PID set temp is not over shot.

    But it is a set it an forget it setup. Pretty nice for Chicago winters.
     
  13. rtom

    rtom Meat Mopper SMF Premier Member

    you might want to stay with a solid state relay over a mechanical with coil. Solid states can handle more cyles JMO
     
  14. nickelmore

    nickelmore Smoking Fanatic

    I had more concerns about the electric element taking the surges from cycling.

    The PID controller can auto tune and was New in box and given to me for free, it said relay control so that is what I went with.

    I figure the relay at twice the amperage, hoping to extend the life of it.

    Any PID advice would be appreciated.

    Hope I am not stomping on Solars thread, but I think he is having the same questions.
     
  15. solaryellow

    solaryellow Limited Mod Group Lead

    That is exactly what I was looking for. Thanks BBQ Engineer! [​IMG]
     
  16. solaryellow

    solaryellow Limited Mod Group Lead

    Not at all. Primarily the thread is self-serving in helping me figure out what to do but ultimately I am pretty sure it is going to help some others out later on down the line.

    My PID questions will come soon enough I am sure. Better to have the answers ahead of time to the questions I don't know enough to ask about today. [​IMG]
     
  17. silverado2100

    silverado2100 Fire Starter

    on our smoker one hot goes directly to the burner and the other is switched, thats how the diagram showed it. ill see if i can find it.
     

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