1kg Steel Melting Furnace on eBay

For those of you who might be interested, we just listed a new small steel melting induction furnace (1kg capacity, fast melt) on eBay, item #

200115158055. This unit can be run using household power. Here's the eBay link:

Tim

--Just outta curiosity does anyone know how much power it takes to melt 1kg in an induction furnace; i.e. what's the electric bill like?

If you have to ask you can't afford it...

I heard the electric bill for one of our data centers runs about $250k... per month!

Pete C.

As mentioned by another poster, at 5kW and assuming $0.06 per kWh (as it is here in Vancouver), that would translate to about $0.30 per hour (yes that's

30 cents per hour). I'm not sure which system the 250k number is based on but I know that it takes almost nothing to run this small furnace - there are customers that run these machines in two 8 hour shifts every day in the jewelry industry.

Tim

(220-230 V

Melting cast iron with my induction furnace I recently used 3.8 kWh to melt a 3Kg ingot - having fitted a re-settable kWh meter to my 100kVA diesel generator I make a habit of resetting it before each melt. Obviously s/s will be more as the melting point is higher, although the latent heat of liquifaction may be a bit less.

AWEM

Where did you get it and how much did it cost?

Wes

100kVA

What? The ingot, or the generator, or the kWh meter, or the induction furnace. !

The answer to all of them is eBay, and loads of dosh ! (except the ingot thinking about it)

AWEM

--Thanks for the numbers!

OK, here is a quote from a recent posting of mine in the electrocast group, that breaks down the figures:

Having fitted a digital resettable three phase kWh meter to my

100 kVA generator, I thought it would be amusing to see what sort of overall efficiency I'm running at in terms of electricity input to molten iron output.

A few assumptions:

1/ I melted approx 3kgs of white iron 2/ Ambient temperature was 13 deg C 3/ The iron melted at 1535 deg C 4/ It was super heated to 1635 deg C 5/ Specific heat of iron is 0.449 J/g degK 6/ Latent heat of liquifation of white iron is 138 KJ/Kg (suprising difference with grey iron at 95 KJ/Kg)

There are three phases:

a/ Raise iron from room temp to melting point b/ Stuff in enough energy to melt it overcoming the latent heat c/ Super heat by a further 100 deg C

By my calculations (but please check them)

a/ uses 0.569 Kwh b/ uses 0.115 Kwh c/ uses 0.012 Kwh

Thus a total at 100% efficiency should be 0.696 kWh I measured usage of 3.8 kWh so:

18.3% efficiency

Now of course heat is lost in the electronics, in the walls of the crucible, and in the various cables, but 18.3% is pretty staggeringly low I reckon, especially as it takes no account of the energy being piled into my water cooling plant, nor the 1 hp coolant circulating pump.

If I did the same calculations from the diesel in the generator tank to molten iron, and allowed for the other factors mentioned above as well I reckon I'd be down into single figures of efficiency !!!!

AWEM

Wed May 9, 2007 7:45 pm

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