Heat Treating Oven build

ehmecc

New Member
Hi,

I'm thinking about building an oven. Could someone with more experience go over my calculations?
Chamber dimensions 20cm wide, 10cm tall, 27.8cm deep.

Input voltage: 230V
Wattage: 2700
Amperes: 11.73 (MAX 16A)
Ohms: 19.59

I would be using Kanthal D to make 1 element
1.4 mm
0.877 Ohms per meter

That would require a total of 22.34 meters of wire.
The surface load would be 2.7 W/cm² and the coil ~94cm.
I can fit ~200cm of stretched coil iniside.
 
Hi ehmecc

I am going through pretty much the same sorts of calculations right now. My design uses K23 type insulating bricks with a chamber size of 150mm wide, 100mm high and 390mm long. This is an internal surface area 2250cm2. When I have cut grooves along the sides and rear of the cavity it will be 1.86m long for the element.

In terms of elements I have worked out the following -
Power supply will be 10AMP 240V plug. (I do have 15AMP 240v and 3 phase available but do not believe I need to go to that extent).

In terms of power with my parameters I can go up to 2400W (240v x 10AMP = 2400W)

For safety sake if I go 10% below then I am looking at 2160Watts

2160W would give me 0.96 Watts/cm2 which seems to be at the upper end of comercial HT kilns so I am good with that.

Using OHMS law U²/P=R
240²/2160 = 26.66 Ohms

So I believe I require an element that will be able to be stretched to 1.9m long with resistance of approximately 26.66ohms

I have a local supplier (Australia) that has a 23 Ohm coil I can buy ready to go and I am thinking of doing this and moving up to 15AMP plug. If I make my own I will be doing a similar calculation as you are and will shoot for 26 Ohms.

The 1.4mm Kanthal wire you propose I believe is 0.942ohms/m rather than 0.877 but I may well be wrong - just check to make sure. If it is 0.877 ohms/m then I agree with the length you have come up with.

Please keep sharing your build as I am seemingly in the same boat!

Ian
 
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