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[Zigeuner]

Hello,

I see that many here have converted (or started out with) components such as PID's, SSR's, Heat Sinks and blowers. I also notice that many seem to have problems with heat generated by the SSR's and circuity in general, sometimes leading to failures or innacuracy.

Since I'm just now finishing the mechanical portion of my oven and the wiring is also done, I'm going to be firing my oven up fairly soon. I'm starting out with my original approach which is to use a Definite Purpose Contactor, a Cutler-Hammer C2BNF240A, controlled by a home oven thermostat. With four 2,500W elements (10KW total) at 240 VAC I'm predicting something like 42 amps total. The Contactor is rated for up to 50 amps.

Given the fact that I may wish to upgrade at some point, does anyone have a parts list for a PID, SSR Heat Sink and Thermostat that are matched and which will handle 50 amps without overheating? I'm considering adding a blower also. The oven is 2'W X 3'H X 6'D. (36 cu. ft.) and is insulated with rockwool inside of 20 ga. galvanized steel sheet.

I can substitute these items into my circuit at any point in time so there's no rush. I like the idea of having a good control on the heat setting and possible greater stability. I also don't want to waste any money on items that are under-rated and perhaps will fail.

Any comments will be greatly appreciated.

[ed_denu]

Most any pid is capable of driving an ssr and/or contactor. As you go up in price you get additional capabilities such as ramp/soak, timer, etc. All pids have the capability of handling different type thermocouplers, you just need to change the pid's internal parameter to the correct choice. The 'K' types are probably the most common and are often included with a pid.

As for ssr's, I've been using an ebay model(Fotek) for a couple years without any problems. Many have purchased Auber Instrument products, but there are many choices. Ken recently listed a couple of good heatsink options if you want to search back and find it. The other option is to use a cpu heatsink/fan combination.

Your 10k watt element load will draw the 42 amps you referenced, so I would consider something a little larger than a 50A ssr. Keeping the load at no more than 80% rated capacity is a good target.

So bottom line imo there is no such thing as matched components, just insure that the components you purchase are compatible and of the proper capacity for your oven element load.

[Zigeuner]

I picked up the number for the D.P.Contactor from the below website. I used his basic dimensions and electrical schematic. He has been running his oven with that contactor for quite some time. Mine is built to the identical specification except for the insulation. He used 2" fiberglass board and I'm using 2" of rock wool.

Maybe I'm wrong but the way I understood is that each side won't be carrying 40+ amps. I think it will be divided between L1 and L2. Nonetheless, I'll see how it works since I paid $38 for it. LOL.

42 amps is 84% of the 50 amp rating in any case. That's close enough for government work.

I will also have the unit on a 70 amp dedicated line (shared with a welder but not used simultaneously) with three single 0 cables plus a double 0 ground from my main panel to my subpanel and 6 ga. wires thereafter to the oven.

Home

[CarWiz]

Originally Posted by Zigeuner

Maybe I'm wrong but the way I understood is that each side won't be carrying 40+ amps. I think it will be divided between L1 and L2.

Huh? Both sides carry the full load. Your load is connected between L1 and L2, I hope.

[Zigeuner]

Originally Posted by CarWiz

Huh? Both sides carry the full load. Your load is connected between L1 and L2, I hope.

OK, I'm still good since I'm pulling 40-42 amps on a 50 amp Contactor. I was hoping to get actual part numbers on solid state components but I'm sure I can find them.

Thanks anyway.

[ed_denu]

Quote: 42 amps is 84% of the 50 amp rating in any case. That's close enough for government work.

Not imo. I would still suggest you go with an ssr larger than 50A, or you are going to need a very good heatsink.

[Zigeuner]

Originally Posted by ed_denu

Quote: 42 amps is 84% of the 50 amp rating in any case. That's close enough for government work.

Not imo. I would still suggest you go with an ssr larger than 50A, or you are going to need a very good heatsink.

That's another good idea....a heat sink. I've got plenty of room for one and there are dozens of really large ones at a local surplus store. I'll go grab one.

Yeah, I want to see how it goes first. Likely, if I make changes, I'll just change to PID/SSR internals and have done with it.

I've got the top, sides, rear and front door stuffed and covered now. Just have to reassemble and add my lights and IR shields over the elements.

Thanks.