Wiring Oven

[TemperanceCoaters]

Ok, heres the deal. Me and my buddy have been powdercoating for a while now but keep running into some trouble here and there. And i finally found a good site to come to. I will post some pics of our oven a little later today after i wake up.
But, on to the dilemma. We have a kitchen oven next to our homemade oven. We switch back and forth between the two ovens depending on parts. Our large oven is 6x4x3 in feet that is. We have 4 elements mounted into our oven, but we dont use all 4 because we dont think our oven can handle it. Is there a better way of hooking the elements up? Right now we just take the wires out of the back of the small oven and hook them up to the elements in our large oven. Is there thermostats and what not we can buy so we dont need to switch back and forth?
Any info would help out.
http://www.powdercoatoven.4t.com/con...on%20page.html
That guy has a nice picture of wiring but i dont know what a definite purpose contactor is.
Any help is appreciated and ill get pics later today.
Heres one i found


Now our oven is vertical and has a rack on wheels.

[Crimson]

The Contactor
http://www.famousparts.com/c25bnf240aco.html

[jrow]

TemperanceCoaters,

The contactor is a 240V switch activated by a 120V source. The "S" in the diagram activates the contactor. By the way thats a real good price for a contactor.
If you can got to an 'electrical contractor vendor' and look at a contactor like the one that he used, it will become self explanitory!

I think Gary Brady should be complemented on his drawings and the construction of his oven. It's a real bute.


John

[TemperanceCoaters]

Ok, the one you showed me is 40 amps but 120 coil? Dont we want it set up on 220 for out oven? Im gonna go get pics of the oven right now and post em up so you guys can help me a little more.

PS, im 19 and have no electrical background, i dont understand that drawing either.

[cdaeme]

Originally Posted by Crimson

The Contactor
http://www.famousparts.com/c25bnf240aco.html

I'm no electrician so if I am not 100% correct someone please chime in. If you can print off the diagram so you can follow the connections as I explain them.

If you look at the drawings. L1, L2, N, G. is your incoming power. 220v power is comprised of 2 110v lines a neutral wire and a ground. Lets focus on L1 first its 110v and it branches off, one wire goes directly to the (C) contactor and the other goes to the (S) switch (This will be your on/off switch) then to the (T) thermostat (temperature control) then to the coil on the contactor. This part of the circuit works like this - You have 110v to the Switch when you turn the switch on it now flows 110v to the thermostat if the temperature is below the thermostat setting then the 110v flows to the contactor coil which will engage the coil (more on this in a minute). When the temperature reaches the setting on the thermostat the thermostat will break contact and no longer sent 110v to the coil as the temperature drops below the thermostat setting it will make contact again energizing the coil again.

Now for the contactor as you can see L1 and L2 go directly through the contactor and out the other side. On the inside of the contactor the circuit is not made until the coil is engauged (in other words the connection is broke inside until the coil is engauged). When the coil is engauged you now have 110v on L1 and L2 going to your elements. L1 should go to one side of each element and L2 to the other.

The (N) neutral completes the 110v circuit for the coil which works like a magnent with 110v it will pull the contacts into place and complete the circuit for L1 & L2 through the contactor.

The (G) ground is for your protection if something with voltage shorts out or makes contact with the frame it will trip the breaker. Without the ground if something shorted you might not know it until you touched the oven and suddenly became the ground. (This is not fun!!)

The connections on the elements should be self explanitory if not let me know and I will try to help with them also.

It's good to see young people taking some innitative. Take your business seriously be honest and always wear the white hat and you will go far. If you would like to contact me directly contact info is on my site.


Jason Williams
www.autocyclepc.com

[TemperanceCoaters]

Thanks, that helped alot. Will that contactor shown work? If so im going to order it. Also, how do i figure out how much power my elements are pulling. Im uploading pics of the oven right now.

Heres the pics of the oven.



It was made out of 2" Insulated sheet metal with a concrete like finish on the inside. Works very nicely and we dont lose very much heat.

And we do take this seriously, me and my buddy hope to open up an actual shop and do this for a living.

[cdaeme]

The amperage draw goes a little above what I can explain but if you will do a forum search for element size or amperage you should get some posts that have discussed that alraedy. I will look myself and if I find them I will post some links. I too am just getting started and hope to expand into a full shop of my own. I'm 34 now and only wish I had started something like this at 19..


Jason

[cdaeme]

About halfway down this thread is the formula you need. wattage requirements With 4 elements you will probably need a 60 amp breaker and the contactor will need to be 60 amps also for that price on a contactor you could probably buy two and separatly wire 2 of the elements on another switch. That would give you the option to only run 2 elements if you want. Nice oven buy the way I wish I had one that size already!!.

Jason

[pickleboy]

oven looks good for starters my only concern is the mismatched elements. this may be a concern. generally speaking the shape has to do with the design of the original oven they came from. what i am trying to say here is they may not all be the same wattage/ heat range. if this is the case it could cause hot spots in the oven. example: if they were numbered top to bottom left to right, then lets say that 1 is 500 watts, 2 is 400 watts, 3 is 750 watts, and 4 is 600 watts. there might be a time that parts closer to element 3 cure faster or more than parts next to element 2. this can also cause a issue if you wire them in 2 circuits, the circuits should be balanced if/when possible to insure even current flow through the contactors. in the example of 2 circuits running from a 60 amp supply, it should be 2 30 amp sides and not a 40/20 split. i hope this makes sense. also please dont take offense i think you have done a great job so far. i would wire it up and try it out. if you can get a amp probe to test the circuit draw this will help. also when you fire it up for the first time put some scrap metal in the oven at different locations(preferable the same size and material scrap metal. bring them up to temp and check each part with a laser thermometer to see if you have hot spots. i also lastly would think about a fan for circulation.

[TemperanceCoaters]

Yea, the elements are out of 4 different ovens, never really thought about the different power levels. Also we had a fan in there but it wasnt made for heat and partially melted causing it to wobble. The oven holds the heat very well, the outside is only 10-15 degrees warmer than the air temp of the shop.

So is there a place that i can buy 4 new elements? Is 4 elements enough for our oven?