Resurrection of a CFEI 100 KVA Induction Furnace

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awemawson:
Thanks Russ :thumbup:

I'm glad to say, still no leaks despite having the pump running for several hours - I took to turning it off for a bit then back on reasoning that the start up is probably maximum strain - I also varied the pressure up and down. In retrospect it would have been handy to fit a pressure gauge to the coolant system to help notice any changes - maybe later.

I've spent the afternoon wrestling serpents again :bugeye: When I fitted the long umbilical from generator to wall socket I didn't have the right sized cleats to fix it properly, so used some humongous Ty-Wraps. The proper cleats arrived several days ago but the coolant blockage took priority. I also decided to run it on the opposite side of the RSJ as it lay better there. Blooming heavy and although supposedly flexible it still has a mind of it's own.

Next job : sort out the earth bonding . .

awemawson:
Getting ready for a CPC (Circuit Protective Conductor) - or Earth to people of my age making session tomorrow I though it wise to check that the tubular crimp lugs were compatible with my crimper when using the 70 mm CSA cable that I intended to use, as these are unbranded generic ones.

As the cable sheath is Black I'm heat shrinking Green / Yellow onto the ends partially encapsulating the lug as support, and I wanted to check that the 'shrink ratio' brought it down to size.

All's well so let bonding begin . . tomorrow . . I've had too much excitement today :clap:

In actual fact these 70 mm CSA tubular crimp lugs crimp much nicer than the tubular butt splices that I used in making the hose / cable assemblies, with far less 'crimp flash' where a bit exudes and leaves a sharp fin. Same crimper, same cable.

awemawson:
OK Bonding Day !

Simple really, drill a few holes, tap a few holes, crimp a few tubular lugs and shrink some heat shrink sleeving on, what could be easier :ddb:

Well very oddly my Cembre HT45 hydraulic lug crimper (of 1985 vintage) decided that today was the day to start playing up - it was somehow hydraulically locked and would neither open nor close. After a bit of an oily session on the bench dismantling its pump mechanism and its release valve, cleaning and putting it back together normal service was resumed - I'd only used it late yesterday afternoon to do that test crimp, and it was fine then - very peculiar.

So, slight delay starting, but I've decided to bond the Furnace Body, and Chiller Unit to a common point on the roof of the Furnace driver, and from there to the steel frame of the foundry building.

The very fine strands of the 70 mm CSA welding cable that I'm using make it nice and flexible, but it's a bit of a challenge to get the strands all into a crimp lug at the same time and also manipulate the crimper. I hit on the idea of compressing them with a small Ty-Wrap right at the end of the stripped length, then pushing the crimp lug on, which pushes the Ty-Wrap back towards the un-stripped cable sheath. When sufficient is in to be stable I then cut the sacrificial Ty-Wrap off pushing the strands fully into the lug. Unconventional, but it works for me !

So everything in the actual foundry building is now bonded together with ridiculously heavy cross section cable - better bigger than smaller :clap:

Yet to do is bond the Generator, and the frames of the four buildings to each other.

I should perhaps explain:

A/ My Welding Shop is a steel framed 'lean to' added to the South side of my main workshop, and is made of bolted together RSJ's and angle iron, fitted to flying brackets welded to the steel frame of the main workshop.

B/ My Foundry is a steel framed building added onto the west end of my Welding Shop, and although again of RSJ and Angle Iron construction is fully welded but as far as I can tell is 'free standing' as far as the steelwork is concerned, and just joined by the roof so no real electrical connection between the two.

C/ The 'Stable' where my big generator sits is another 'lean to' added to the North side of the main workshop, and is made from RSJ uprights and rafters as three frames, but they are held apart by timber purlins and free standing so again no electrical connection

So bonding this lot together gets a bit complicated. Certainly I will bond the generator frame to the adjacent RSJ frame of the stable, and try and get a cable through the wall to bond them both to the steel work of the main workshop. And I will try and bond the foundry, main workshop and welding shop frames together where they all come together at a corner. But I don't think I'm going to go as far as bonding all the stable frames together - not fully decided - we'll see!

awemawson:
This afternoon, despite interruptions (*) I managed to bond the Foundry steel work to that of the Welding Shop and Main Workshop - this went quite smoothly when I was able to do it !

Then I turned my attention to the big generator. Its main earth terminal is inside the control box down at nearly floor level, but I wanted to bring the cable in from the top through a gland, so that it more directly could run to the nearest RSJ frame. This was a bit complicated as it involved removing the safety covers, the perspex one in particular is a pain to get in and out (I know - I made it, it's my fault :bang:)

I still have to bond the two RSJ frames in the stable to both the generator and the steel work of the main workshop but that's a job for tomorrow - I've had enough!

(* a friend presented me with a bolt - "I'd like one almost like that but a different thread" Well the bolt he had brought was 1/2 UNC and apparently it screwed in a bit but was loose. Now this is off a (possibly) Japanese grey import digger so the thread could be almost anything! It's a critical application as it's holding the main hydraulic pump so best get it right. Pump currently held by one bolt and is too heavy for him to get back in place single handed if removed for measurement. In the end I turned him a tapered piece of delrin and told him to force screw it in, back it out and bring it back for inspection - might work :scratch: )

awemawson:
Another fabulous bright and sunny day, so I was up with the lark, and had finished the last of the bonding between the building frameworks by 8 am :thumbup:

. . . perhaps now I can get on with something a bit more interesting and less neck cricking :clap:

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