Resurrection of a CFEI 100 KVA Induction Furnace

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awemawson:
No Matthew, with the tilting furnace body you either fill a ladle and pour from that, or arrange your moulds at a suitable height to pour direct, in which case it's a matter of raising the tilt sufficiently for the metal to start flowing, and reversing the lever to start descending to stop the flow when the sprue is full.

I managed to clamp the hoses - I can't say I'm over happy with the way they lay - flipping awkward stiff things !

awemawson:
Gentlemen (and Ladies if present!) I have a dilemma :bugeye:

I've been wanting to power up the Radyne and use it, but at the moment I'm completely confused as to it's connections. I'm SURE that I used it previously after installing the new crucible, but the way it's internal plumbing is illustrated in the picture below it CANNOT have worked I think.

I had expected the terminals to map A, B, C, D from left to right and indeed on one photo the extreme right hand pipe has a D on it

As the photo clearly shows, Terminals 1 & 2 are connected ELECTRICALLY as are Terminals 3 & 4 - you can see the blooming great copper horizontal strap between them.

Now the actual induction coil has a deliberate blockage where the nylon reinforced hoses from Terminals 2 & 3 come together.

So coolant entering 1 can ONLY exit by 2 (and vice versa) and coolant entering by 4 can ONLY exit by 3 (and vice versa)

BUT the electrically commoned terminals on the furnace driver are pairs "A & D" and "B & C" with coolant flowing out of "B & C" and returning on "A & D"

So if "A & C" on the driver map to "1 & 4" so that the top and bottom of the induction coil are connected correctly coolant has to come out of "2 & 3"

On the tilting furnace body the terminals that are commoned at it's end correspond to the commoned ones at the furnace driver.

If I screw this up it could be curtains for the driver electronics :bugeye:

So if any of you have been able to follow my confused ramblings - please go logically through this and tell me where I've gone wrong - or have I gone wrong - or did I plumb it up wrongly back in 2006 ? (I can see that if I swapped over the two internal nylon reinforced hoses within the Raydyne it might make more sense :scratch:)

. . . my head hurts . . . .

awemawson:
So in the absence of other suggestions, this morning I opened up the back of the Radyne Tilter, and lo and behold it seems that I'd done a second re-plumbing eliminating the welding cable current reinforcement by using heavier walled pipe. (It looks like I've used 3/4" air con pipe tailed with 15 mm) However the issue remains in that if connected up it would put a direct electrical short across the Furnace Driver - not good.

I 'think' by interchanging the nylon reinforced pipes I have a solution that 'should' work - certainly now no direct short across the driver !

I was able just to uncouple the threaded fittings and move the pipes, but I'm not happy with their lengths as they are touching the copper driver pipes, but I'm out of stock of 15 mm bore nylon pipe - they'll do for test purposes until I can get some more.

So now "A & D" are electrically commoned at both the Driver and Crucible ends, as are "B & C" but the order of connections on the base of the furnace body are a bit illogical reading "C B D A" left to right

I do remember having standard metal Jubilee Clips getting hot in the field of the coil and melting pipes and sure enough the ones on the outer connections of the nylon hoses are nylon clips to avoid this problem, but oddly the ones on the other end of these pipes are standard metal ones

RussellT:
Hi Andrew

I'd just spent 10 minutes trying to understand this when you posted your latest update. I think I agree with where you've got to. Clearly the electrical connections have to take priority and that means the piping wouldn't have worked unless there was something strange going on at the connections on the side of the coil. The other variable I was trying to get my head around was whether there was any significance to the direction of coolant flow - for example to keep the nylon pipes cooler than the copper ones - but I would hope that they would be kept sufficiently cool for that not to be a problem.

Russell

awemawson:
Russell, now you see why my head hurt - thanks for your ten minutes - much appreciated !!!

One 'advantage' of this flow system is that cold coolant enters both sections of the coil at their respective bottom coils and leaves at their highest coil thus circulation is aided by thermal / gravity effects. Whether this is at all significant is debatable though!

Much search for 15 mm bore nylon reinforced pipe so far has drawn a blank. 13 mm no problem. 16 mm no problem. 15 mm no sign :bang:

I am conscious that access to the centre connections on the coil is severely limited so struggling a pipe on would be an issue - the other end access is easy so no problem.

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