Oh Blimey I bought a CNC Lathe !!!!

[vtsteam]

Does that big cap have a bleed resistor? What is its condition -- also the solder lands in that vicinity -- possible cracks?

[awemawson]

Yes - a bleed resistor and a tell tale led to warn you not to kill yourself!

It and all the major power components are bolted to the pcb. Looking at the 'block diagram' which is all I have, there are current sensing low value resistors in two of the three three phase legs, and a third sensing resistor in series with the output from the three phase bridge rectifier where it feeds the 'H Bridge' power fet 'lump' (one big integrated block that looks mega expensive - after all it handles 100 amps peak at 300 volts or so)

As the first error message I was getting was concerning the a/d converter not being happy at power on, and the latest one is 'over current' then it's probably something around current sensing. The actual a/d has been eliminated as I swapped logic pcbs with the other axis amp, as has genuine over current, as I've disconnected the relevant motor and it still complains.

[vtsteam]

I was just wondering why 8 hours vs 10 hours etc. made a difference. For something that specific it sounds like some kind of (inadvertent) timing circuit, which might be traced to the area of one of the bigger caps. Since you mentioned a suspicion of a 2000 ufd cap, and a bleed resistor makes it a sort of timing circuit, i wondered if there was a bad connection or a bad resistor. Heat often disrupts an intermittent due to a cracked solder joint or other weak connection, and since heat also seemed to play a part I thought maybe it was the resistors connection point as being somewhat suspect.

[awemawson]

Yes it is very strange.  Almost as though a capacitor, if it still held charge, prevented the fault, but if it had discharged the fault showed up. This of course militates against curing it by replacing capacitors!

Although hopefully the (large) box of capacitors should arrive tomorrow, I'm probably going to have to leave it until the end of next week before I can attack it. Family 'do' starting tomorrow with 60 relatives descending on  us Fri / Sat / Sun. Clear up the mess Monday and off to spend a couple of days in the midlands on Tuesday so I can pick the brains of the bloke with a clutch of Traub lathes - so not back till Thursday evening

You never know it might have fixed itself by then 

[vtsteam]

What if an electrolytic capacitor had a short that appeared when the plates had been absolutely fully discharged, but the short tended to heal momentarily (if the rest of the charging circuit momentarily allowed it) when the cap was again charged  -- and remained when even very slightly charged, for say 8 hours max. after shutdown. But this ability degraded until the charging circuit could no longer support charging the cap, reporting over current?

[awemawson]

Yes a possible scenario. I'll have to contain my impatience until the back end of next week before I can delve into it. I did at least yesterday print out and fix suitable cable labels - the masking tape I'd temporarily used last time was getting tatty and illegible. There are a lot of screw terminals close together in an awkward low down position and to make an error would be very easy.

[awemawson]

All the myriad of house guests seem to be sleeping in this morning so I crept off to the workshop 

The cooling system has been a bit of an unknown - a big lump called a Schroff RHB 3000 bolted on to the end of the cabinet, taking in warm air from the top, and blowing it out cooled at the bottom of the cabinet. Certainly lots of air flow but I wasn't convinced it was actually cooling. I had thought that the whole thing was a factory sealed item, but yesterday when showing a nephew the lathe I realised that in fact it had a totally enclosing cover that could be removed. Hence creeping away this morning to investigate.

Taking the cover off let me gain access to a termination box that among other bits houses a contactor - contactor not pulled in, cooling compressor not running! Jamming contactor armature over into the 'made' state with a screwdriver the compressor starts up, and air coming in at the top at 25C is now exiting at 14C !

The problem can only be either one of the thermostats, possibly the contactor coil, or one of the various trip devices in series with the coil, but daren't start investigating now or my absence will be noticed!

This may account for the failed X&Z axis servo as it is first in line for the cool air.

Anyway - a few pictures

a/Over View with cover removed
b/Close up of control box
c/Circuit diagram thoughtfully provided by Schroff and glued to lid of control box!

[Pete.]

Was there anything on the machine that actually worked as intended? It seems that every part has (had) a fault of some kind.

[awemawson]

I think it is just an accumulation of issues that people have worked round rather than fixed. In the case of the chiller unit it probably failed years ago and no one was sufficiently switched on to notice - in most climates it probably wouldn't matter. Being rather anal I am checking and double checking everything, so probably teasing out things that had gone unnoticed. For instance I asked the previous owner if he had had the x1000 issue with the Automatic Toolsetting - he said he had never used it - yet it is the most useful facility saving loads of time !!!!!

[vtsteam]

Some people like jigsaw puzzles. But you only get a picture out of that. Or a Rubix cube, where the satisfaction after solving amounts to finally lining up some colors.

Figuring out what a list of brief misleading phrases refer to will be the personal reward for the crossword puzzle fan.

Then of course you could spend your time making an industrial size, quality and value, precision piece of computerized manufacturing machinery work as once intended.

Not appealing to many. But, nice that it is for someone. With the capability.

[awemawson]

You are right Steve - it's the journey I enjoy, not necessarily the end product. A bit like the question 'why do you climb mountains' Ans : 'cos they're there !

Anyway:    Chiller issue now resolved   

It was high resistance contacts on the thermostat.  A bit of contact cleaner and tweaked the trip point up and down a few times and it's back working. It has probably sat for years with open contacts awaiting that hot spell to close and start the compressor, and when it did the contacts had oxidised. Must have been quite a build up as the coil it switches is 415v, so a good wetting voltage you'd think.

Now as the cabinet doors are still off it is trying to chill the entire workshop, and drying the air, producing a stream of condensate from its run off pipe such that I've had to put a bucket under it. Long term I'll plumb it outside, and duct the hot exhaust air outside as well (perhaps with a diverter flap to inside for the winter!)

[Pete.]

What I want to know is - how did you convince a stranger to let you wander around his workshop for two days distracting his operators and drinking all his tea?

[awemawson]

No convincing needed - he invited me. I'd been told by a machine tool dealer that he had the Traubs and I rang him to ask for help.
We've arrived in the area (staying here tonight) and I'm writing this sitting in the wife's motor home overlooking the River Nene watching the Geese billing and cooing.
One of those odd coincidences happened today. We drove past this chaps factory to see where it is on the way up. Turns out the very next door unit is occupied by a company run by a fellow I've never met but corresponded with in newsgroups for many years. John S will know him - Peter Forbes.  So I'll call in tomorrow and pay him a visit.

[John Stevenson]

Yes another odd coincidence is that I have to belt down to Northants tomorrow, NN6 area, to pick a wood burning stove up.
With all these thunderstorms the temp has dropped from high 34 to low 32, can't be having with all this cold weather.

For all those that like a bit of steam punk.

[Bluechip]

That's nice, John ... 
 
All we need now is a piccy or two of you in your  Marigolds sloshing Zebo on it ... 
 
 
Dave BC

[Pete W.]

SNIP

 and I'm writing this sitting in the wife's motor home overlooking the River Nene watching the Geese billing and cooing.
 
SNIP

Would that be anywhere near the Billing Aquadrome by any chance?          

[awemawson]

Indeed so close I can hear the jet skis in the distance!

[Pete W.]

  

As I remember it, in those parts the name of the river is pronounced 'nenn', whereas downstream nearer to Peterborough, I understand it's pronounced 'neen'.

In a past age, I had family in Cogenhoe (pronounced 'cookno'!).   

[AdeV]

One of those odd coincidences happened today. We drove past this chaps factory to see where it is on the way up. Turns out the very next door unit is occupied by a company run by a fellow I've never met but corresponded with in newsgroups for many years. John S will know him - Peter Forbes.  So I'll call in tomorrow and pay him a visit.

Coincidences abound... I've met Peter a couple of times; once to pick up a Lister engine & one to drop off some old Austin A40 bits... I've never seen his factory though...

If perchance you see this in time, please say Hello to him from me.

Cheers,
Ade.

[awemawson]

AdeV, yes I met him. Turns out that the chap I was visiting is Peters landlord! Unfortunately I wasn't able to concentrate much talking to him - suddenly got excruciating groin pains. 999 call and an ambulance later it seems that I have a hernia Upside is after they attended within 45 minutes everything went back in place and normality returned. Quelle relief !

The other bonus was that John S was in the area, and he, and my wife and I ended up having a nice meal together at a pub recommended by the ambulance crew !!!!

I came back clutching several Traub manuals (borrowed for copying) and these splendid laser cut labels curtsy of Mr John Stevenson.

[vtsteam]

Yikes!! Scary. But glad you're okay!

Those must be some heavy manuals.....

Labels look great.

[Pete W.]

Hi there, AWEMawson,

Sorry to hear of your distraction (putting it mildly!) and I hope that there's no recurrence.  Does this mean that you're headed for a spell in the bandage factory?

[awemawson]

Thanks chaps for the concern.  Yes referred to the surgeon this afternoon and awaiting a date for the green dressed highly paid craft knife wavers! But let's face it it's a run of the mill bit of butchery these days

Hopefully , now I'm back from my jaunt I can get to grips with the X servo driver and fix the over current problem. I also need to finish off those Versatool cabinets - the paint should have cured nicely by now.

[awemawson]

  Well things they are a happening 

Firstly: I scored TWO of the axis servo drives on ebay in the US - they are the slightly lower powered version used on the V axis, but the vast majority of them is the same as the higher power one that I have the problem with, including the pcb that I'm 90% sure is the problem - at least it gives me ample spare parts to go at !

Secondly: The chap who I got the machine from has decided to dispose of the original bar feeder that came with the machine when it was delivered in 1993. This is a magazine type that can accommodate a rack of 1 metre long bars, and under program control shove them up the spout to produce widgets en masse. Collection arranged for Tuesday 

Thirdly: The Versatool cabinets are finished and I can see my floor again having stashed all the tooling away. I even wired in a fixed 3 phase 415v 32 amp supply to let me dispose of the trailing cable I've used up until now - can almost move around the shop without falling over !

Now the issue is that the barfeeder needs 75" from the chuck end of the lathe, and I only have 34" in my workshop !!!!!! So it looks like the machine (all 4 and a bit tons) needs to move further into the shop, as do all the machines further up the shop. Any beefy volunteers with toetectors?

[tekfab]

Any beefy volunteers with toetectors?

Why ? are you wanting it kicked into place ?   ;-)

Mike