Oven Heating Problem

[Popeye]

You figured it correctly.
4 heaters at 2500 watt is 10kw or 10,000 watts. You said 110 so I assumed you have a 220 volt service, 10,000 by 220 is 45.45... but now it's 240 which 41.6 would be right

[petshe25]

Popeye,
You were right, I typed in 240 but it is 220V.

[petshe25]

I checked my voltage at the element block and I am getting 231 volts. I also checked the ohms on each element and they are around 24 ohms. With 36 amps I am around 8,000 measured watts which I think are low. I looked at the Caswell ovens and the 96 cu ft. one has 15,000 watts and a 60 amp breaker. I think I am going to update my service and give it a try.

[Popeye]

Yep, the amps are low, you should be around 43amps at 231 volts.. it's normal to for the amps to drop a tiny bit when the element is hot but not that much. You're missing almost 7000 Btuh.
You ohm'ed the elements disconnected, correct? You might want to call the manufacturer of the elements and see what the normal resistance is..

[petshe25]

Yes, I ohm'ed the elements disconnected. I tried a test last night by adding one more 3200 watt element. I was able to get up to temp in 1/2 hour. Alot better than the 1 hour and 10 minutes. I am going to do an amp test tonight to see what draw I have now with the 3200 watt attached. It looks like if I am only drawing 36 amps with the (4) elements, it is only about 8,000 watts. This should bring me up to 11,200 unless I loose some with this element also. This could bring me to 48.4 amps which is pushing the limit of the 50 amp breaker without a safety factor. Another question about the powder itself. Does the powder start to melt at a certain temp on average? Just wondered if it needs to get to 300 - 350 before it even starts to melt.

Thanks,
Pete

[edwardpic]

sure am, we are using(6) 1500W strip heaters from McMaster. I have pics of the elements of you want to email me. Remember we are running 240V 3 phase as well.

Ed
rynomobilitycorp@aol.com

[jrow]

petshe25,

I haven't noticed in this post as to what gauge wire you are running? Are your wires getting warm (hot) when your oven is on?

John

[petshe25]

John,
I am using 6 gauge wire from the breaker box to the contactor and 10 to each of the elements. I just bumped the breaker up from a 50 amp to 60 and bought a 4 pole 40 amp per side contactor. Since these elements are drawing 9 amps each, I ordered 2 more today which should bring me to 54 amps total. We powder coated a test piece today and at about 20 minutes it began to melt and we took it out at 40 minutes. We didn't make it to the 400 degree mark but the part was fine and had cured it in the 40 minute total time. None of the wires got hot or warm. Only the breaker itself was warm. Later this week we should be able to try it with all 6 elements and see if it heats up any faster.

Pete

[dbug10]

the 3 phase wont have anything to do with the btu of the elements 10kw is 10kw no matter how you power it i was just wondering if i have to much heat in my oven if i could cut back to two elements?