100Kw CFEI Induction Furness

[awemawson]

eskoilola's thread on building his induction furnace awakened my interest in this subject, and to my amazement I found that I still have pictures of my setup from 2006 when I was working on mine before we moved here 11 years ago.

Rather than hijack his thread I thought I'd post the pictures here.

. . . . maybe when / if I've finished the Beaver TC 20 CNC lathe this might be the next resurrection thread 


The big blue box takes in 3 phase 415v AC power, and rectifies it and resonates a tank circuit, the coil of which is wrapped around the crucible, and the capacitor bank is in the box. The resonant frequency is determined by a microprocessor that pings the tank - measures the frequency then excites it at this frequency - the required frequency varies with the charge of metal in the pot

The 'furnace body' is remote from the driver and connected via 70 mm CSA cables that are threaded inside rubber 'brewers hose' that have water pumped down to prevent the cables melting (huge circulating currents involved). There is a separate chiller unit that keeps the water cool.

[awemawson]

In fact I have two 'furnace bodies' - one is arranged to tilt to pour in a conventional manner, where as the other inverts - the mould being clamped to the top so the metal is never exposed to the atmosphere.

The pouring one I totally rebuilt and upgraded the tilting mechanism using 'air over hydraulic' control

It would be fun to get it all fixed up again sometime . . . . .

[mattinker]

Great stuff Andrew, this was the project where I got to "know" you, please resurrect!!

All the best, Matthew

[awemawson]

It is very tempting Matthew but there are things ahead of it on the 'round-tuit' list

[eskoilola]

Ahhh....
I am rather surprised that I quessed correctly the setup of the heater coil in relation to the crucible. There is a reason why it sits on top of it instead of being casted as a part of the crucible. Thremal expansion of copper is quite a lot larger than that of the crucible material. Built this way the crucible will not crack as the coil can expand when it warms up.

Thanks for these pictures !

[vintageandclassicrepairs]

Hi Andrew and All,
Not directly related to this thread but it reminded me of when I worked on Alstom Generator rotors
Induction heating is used to expand  the rotor end bells for removal and refitting
Water cooled cables are wrapped around the end bell and fed from 2 phases of the station standby diesel generator, I cannot remember the power needed but the diesel engine was a V12 with a massive turbo on each bank of cylinders, It was such a smooth running engine a 50p coin sat on edge on the engine block stayed there, the noise was something else though !!!

John

[hermetic]

where the devil do you get this kit! I am so jealous, it even has a big turney wheel on it! I am afraid it would turn my 100A three pahse supply inside out, wouldn't want the electric bill, but that is a real pro piece of kit! Cold running water, and hot running metal on tap!

[awemawson]

Well Phil, at the time I was struggling to make my own invertor furnace driver using massive IGBT's - it worked but was very inefficient. But I had a search set up on ebay for quite a while for 'Induction Furnace' - this one popped up several times and failed to reach it's reserve so I opened negotiations - I honestly can't remember what i paid - it wasn't a give away but far far less than the chap was initially asking.

However I ended up building a building to house it at the old place, buying an Agrecko 100 kva generator that I had to rebuild, and rebuilt the furnace bodies including commissioning custom crucibles.

Then I moved, built ANOTHER building to house it but haven't actually re-commissioned it (yet Matthew!) so I hate to think what it's actually cost me 

. . . . one day  . . . .

[Homebrewer]

Andrew you have some of the neatest stuff squirreled away in your shop!

Sent from my SM-G950U using Tapatalk

[awemawson]

Just found my files on this project - looks like I paid just north of £2K  for it including transport. I have quite a comprehensive manual that I had copied by a charming mademoiselle (that I managed to converse with in broken French)  all those years ago, that gives all the electrical connections but doesn't include the electronics  main board save for inputs and outputs to it. It does however fully cover the operation of the unit - not that it's that complicated.

[hermetic]

Well for what it is, and what it must have cost to buy new, I dont think that is a bad price at all! The only killer is the demand it would place on your leccy bill, but I suppose it is very quick so a pot of molten cast in 5 minutes?  I can't wait.