The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
awemawson:
So this first of the 'fault indications' that I linked out yesterday is solved :thumbup:
Taking my handy Telecoms cable tracer to the job I followed the wiring to where, according to the circuit diagram, there is a simple link between the 'Saphyr Monocrate' digital input, and 24 volts. No! The cable wanders all over the place ending up on an undocumented 110 volt contactor where this 'link' is the one and only used contact. But what drives the contactor?
Again using the cable tracer lead me a merry dance ending up on a 3 core cable Ty-Wrapped to hoses deep in the back of the one panel that doesn't open :bang: Poking a camera in showed some sort of junction again Ty-Wrapped to the underside of the hose with a black cable emerging next to the hose to / from the water flow gauges. Ah - the penny dropped - the flow gauges are not just visual, they have a magnetic float that operates a reed switch THAT OPERATES THE CONTACTOR :clap:
Some rare earth magnets and masking tape simulated water flow, and sure enough that's one "fault" knocked on the head :thumbup: I must have been through this process all those years ago I suppose, but it's lost in the mists of time.
A quick cup of coffee and on the the next fault chain - the temperature sensors.
John Rudd:
--- Quote from: awemawson on April 11, 2020, 05:37:59 AM ---So this first of the 'fault indications' that I linked out yesterday is solved :thumbup:
Some rare earth magnets and masking tape simulated water flow, and sure enough that's one "fault" knocked on the head :thumbup: I must have been through this process all those years ago I suppose, but it's lost in the mists of time.
--- End quote ---
I love a bit of fault finding, keeps the old grey matter working.... :zap:
So I hope you are going to document all your findings this time... :coffee:
awemawson:
Well John this is all VERY odd !
I've spent quite some time cable tracing - some of the temperature switches are literally impossible to get at, they must have been fitted before the machine sub-assemblies were joined, and others required quite a bit of contortion to get at.
BUT I found a switch on the water inlet manifold that was open circuit and accounting for that series line of about five switches not being pulled to +24 volts hence the error. I pulled the wires off the switch and linked them proving the 'fault'
However, when I finally got a spanner onto the flats of the switch and got it out, it turns out to be a pressure switch monitoring the inlet water. So hiow the heck all those years ago did I manage to 'Ping' this beast with no water source and certainly no pressure on that switch - VERY ODD.
Anyway at least I've found what's doing it - now I need to decide how to proceed. :scratch:
awemawson:
So having tested that it works, I returned the water pressure switch to it's place on the water inlet manifold, but left a very obvious jumper link across it to prevent me forgetting I'd done it.
This afternoon I dug out the hoses that used to run between the (now defunct) Water Chiller and the Furnace Driver - you may remember, when I first got them from their rotten storage pallet they had been eaten by rats. Well it turns out that the damage was confined to one pipe only, fortunately the longer one (previous location had dictated unequal pipes) and less than 24 inches from the end. I was able to re-terminate that hose with the existing fittings and make two equal length hoses. Tough to press in those barb fittings, but much aided by Lambing Birthing Gel - basically agricultural KY Jelly :clap:
So if I ever get another water chiller at least I have a starting point for the hoses.
Hence now the hunt is on - I need a water chiller that will provide water thus:
- 25 litres /minute
- 3 bar minimum pressure
- 5 bar maximum pressure
- 40 deg C Maximum temperature
- 5 deg C Minimum temperature
The previous one consumed about 11 kW and provided 39 kW of cooling - I always felt that that amount of cooling was barely sufficient however I had interposed a second heat exchanger in the form of a domestic central heating system copper hot tank as a sort of negative thermal store, but I now suspect that the actual problem may have been thermal transfer (or lack of it!) between the main tank and it's internal coil.
So those of you who scan commercial on line auctions can you please give me a 'heads up' if you see any big chillers listed.
awemawson:
Happy Easter everyone.
At a bit of an impasse until I can sort out the cooling so I've turned my attention to sorting out the foundry itself.
This morning I have removed EVERYTHING not directly foundry related, (and some that are!) to generate floor space, and have moved all the equipment up to one end of the building. I was even able to open the small pedestrian Roller Shutter Door for the first time in years - if you look through it, the round plastic water cistern is what I used to use as a duct sitting upside down on the Water Chiller with a large rectangular hole in it's side holding galvanised duct to the outside world. And inside it I'm glad to say I've found the safety cover that keeps fingers off the Driver output terminals.
This has allowed me to sweep half the concrete floor, vacuum it with the workshop vac and give it a coat of Sodium Silicate to hopefully seal it a bit and stop the dust rising. Google gives me contradictory advice regarding dilution ratio, but I used 1 part very syrupy heavy Sodium Silicate to three parts water. That half of floor so far has used 2 litres of concentrated Sodium Silicate.
Will it work - well again there's contradictory advice 'out there' - so long as it dries it's can't hurt at least :scratch:
. . . so now off to plot and scheme cooling methods - joules / kilowatts / degrees Centigrade and all that stuff !
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