warco lathes.

Edited By Michael Briggs on 25/04/2017 20:44:22

I remember looking in a Quad amplifier, the wiring was beautifully neat. Having also looked in quite a bit of Japanese big brand gear they take a rather different approach, spaghetti comes to mind, I believe the justification is it reduces pickup but I haven't heard many complaints about Quad's gear.

Mike

Really interesting photos and many thanks to Antony for publishing them. I'm still baffled : the striking thing is that only the earth wiring is damaged. In best CSI style, and with thanks to Les Jones' who got in first:

1. A heavy current passed to earth causing severe damage to the earth wires
2. The mains fuse did not blow, nor did anything else protective on the lathe
3. Line and Neutral wires appear undamaged.

That combination suggests that the source of current was not the lathe itself. If it was the then other wiring should be damaged too. Is it possible that something else earthed through the lathe? Being struck by lightning is my best guess. Any more sensible ideas?

Dave

Edited By Frances IoM on 25/04/2017 21:38:09

Edited By Frances IoM on 25/04/2017 21:45:55

Slight diversion but this picture shows the wiring of a 1920's radio.

As was best practice when the radio was made, the original wiring is routed at right-angles and has no insulation. (The insulated wires are modern.) Although It looks neat, it's a really bad idea because at higher frequencies the wiring adds so much unwanted capacitance, inductance and spurious coupling that all sorts of weird problems occur. The best wiring takes the shortest route, and some older quality equipment really does looks like spaghetti inside.

Dave

THIS IS CLEARLEY A FAULT EXTERNAL TO THE LATHE WHAT TYPE OF SUPPLY DO YOU HAVE

It looks to me like the high fault current passed through the earth wire that comes in through the cable gland in the fifth picture. (Next to last.) I think the burn marks on the other earth wires have been caused by being close to this wire as the marks are only in small patches on these wires. Tony, Is the cable coming through this cable gland the incoming mains ? Or does it go to something else ? (If so what does it go to ?)

Les.

The barrack room lawyers are running away with themselves.

None of us actually know what the fault with the machine was - even the purchaser. It is not right to leap to the conclusion that someone is selling faulty, illegal or dangerous goods on the basis on one failure however dramatic, when we have no idea what the actual fault was.

Conceivably it could even have been a mouse chewing a wire - it happens - and would that have been Warco's fault?

Please keep level heads.

Neil

.

Thanks for posting the photos Anthony.

If you had not told us otherwise when asked about any welding taking place near the machine and informed us that none had I would have guessed that the lathe had been put into a low speed and used as a kind of horizontal welding rotary table to have caused that much damage to the earth conductors.

But as this not the case it's a puzzle.?

Nick

My own conclusions have already been posted - absolutely all damage within the lathe means the fault lies within the lathe.

My garage is fed by a three phase supply from the house via a very large cable that cost over a thousand pounds just for the cable (no short cuts here). I have no idea how it is earthed would assume through this cable.

thinking about it I have a large single phase mig welder and a very large three phase plasma cutter, (neither was used prior to the incident for at least a month) surely if there was an earth fault on the building these would have shown it long before the much smaller powered lathe did / would.

I went into the garage to practice the thread cutting I had just learnt at Axminster , turned on the lathe at the wall and turned on the radio, nothing else other than lights & rechargeable battery's in their chargers was in use.

My garage is large enough to have two separate ring mains to share the loads around the phases and the chargers were on the other one as is the mig when in use. the lights are on the third phase.

About 30 seconds after turning the radio on the power went off, i walked to the far end of the garage some 80 feet and reset the trip, it tripped again instantly, As the radio was turned on second i unplugged it and tried the reset again, again it tripped, (just realized when writing this the radio doesn't have an earth wire) I went back to the lathe to check it and went to unplug it and then noticed that the wire was all melted it was down the back of the wire and not easily visible without looking closely as only around 6 inches of cable was clearly visible when plugged in, the sockets are all wall mounted around 4 feet high off the floor. and the cable hangs down from this behind the lathe dro area, there was no trapping of this cable.

that's it that's all that happened no warnings no smoke that i saw ( I do have poor peripheral eyesight ) no flashes or bangs no burning smell until I bent in toward the plug. and then later when I removed the cover it was much stronger but put this down to the confined & enclosed area within the box.

Neil

As you say mice can cause untold amounts of damage to wiring, particularly in vehicles, but there have never been any signs of any mice in my garage (or i'd have charged em rent)

tony

Edited By Antony Powell on 26/04/2017 09:06:33

Well said Neil.

I have read the later part of this post which is in no relate to the start and to be honest there is only one poster who i would take electrical advise from, the rest are amateurs in my book.

As regards Trading Standards that is a complete joke. In my area, South Derbyshire there are two officers, actually really only one and a clerk to cover the whole area. Now if you roll up to the offices with a shoe where the sole has come off you stand a chance but a lathe ??

No way they don't have a clue what a lathe is and chances of a home visit to look at one are zero. So unless you can tuck it under your arm, make an appointment and take it in, only for them to stare at it totally clueless forget it.

Edited By John Stevenson on 26/04/2017 09:33:27

Hi, I am coming to this late but have you considered that there may have been a line fault by the service provider. We had something similar down here when one of the three phases developed a fault at the local village step-down transformer which went to a very high voltage on the line causing similar problems.

Every third house was involved and it fried selective appliances in each house - the service provider ended up replacing large number of appliances at their cost.

We also had a similar thing take place during a thunderstorm where a line surge did a similar thing.

Non earthed (ie double insulated appliances) were not affected. This may have been as the potential difference was between line and earth not line and neutral. Which also explains the earth line damage.

It would be worth investigating as whilst natural surges due to lightning strikes are an act of god - faults in the suppliers equipment are not.

It is easy to jump to the conclusion that the fault lies in the lathe but I have my doubts. 230V line to earth faults will trip the RCD in less than 40mS if the RCD is working correctly and looking at the damage the earth fault current was hugely in excess of that and it may be that the earth fault current was greater than the rated capacity of the RCD or MCB protecting that circuit and therefore could not disconnect he circuit in time. It would be worth checking the fixed wiring on that circuit as well.

Have a word with the supplier or neighbours to see if they experienced anything.

Steve

It is perhaps worth also reminding at this point that per his post on page 3, Warco are taking the lathe away and giving Antony his money back.......

David, your point is ......?

I had come to the same conclusion John, he also posted on page 3 .

That a line fault may be relevant ; but involving trading standards, or if it was a wiring fault solely within the machine (something which nobody knows) are now irrelevant due to the fact that Warco are giving a full refund.

The lathe gets used around three hours a week every week (i did have a spell off due to illness for several weeks) some months ago, but it has worked fine every time it has been used up until the last time.

As I said I cannot see other very heavy kit failing to show an earth fault up long before the far smaller lathe faulted

The plasma cutter is a beast and is capable of and does cut 50mm plate so surely any electrical faults or potential faults would show up when this was used.

Again as i have previously said everything has been checked out by a fully qualified and experienced electrician since this issue and all was passed A1 no fault found

The only comment he made was how clean and tidy I kept my workshop....

Tony

Very true; it's all too easy to jump to conclusions after confusing fact, evidence, opinion and prejudice.

Engineering, Science and Mathematics are disciplines, that is done properly, they depend on evidence, careful analysis of evidence, testing, publication for peer review, and, ideally, some form of proof. Engineers know that lots of time and money are wasted by getting root causes wrong and applying the wrong solution.

In this example it would be inappropriate to throw rocks at anyone, be they the Chinese Manufacturer, the British Supplier, the Customer, the Customer's electrician, the Power Company, or the Deity. (It's possible that this is an Act of God, such as mice and Lightning.)

But it's an interesting case. Tony's follow-up description shows his workshop to be well out of my league. He has a dual ring main and a three-phase supply. He also owns a 'large single-phase MIG welder' and a Plasma Cutter.

I wonder if it's possible that, in use, the MIG welder somehow earthed via the lathe? It's Amps that melt things, and a welder makes them in abundance. The smell of the lathe's melting insulation may have been covered up by the welding while Tony didn't notice anything amiss because his attention was fully focused on the work. Furthermore, the output of a welder whilst arcing is full of flash-bang electrical nasties that might account for the damage to the lathe's electronics. The welder, or rather the possibility of it earthing via the lathe, is my chief suspect. I have no proof of this: it's only a suggestion. If I could suggest a test, then the idea could be promoted to a Hypothesis, which is still short of a proof. Anyone fancy seeing if they can blow up their lathe by using it to earth a welder? Not me!

Cheers,

Dave

PS What JS says about amateur electricians is true.  I am one...

PPS  Could the 'failure' of the trip be explained by Tony's mention of having two ring mains and three phase?  What happens, for example, when power from Ring A earths via Ring B?  

Edited By SillyOldDuffer on 26/04/2017 10:23:24

Edited By SillyOldDuffer on 26/04/2017 10:29:07

Edited By SillyOldDuffer on 26/04/2017 10:30:09

Hi Dave

You seem to be focusing on my Mig when the plasma is probably 10 times the size, the mig is on a completely separate ring main and is around 40 feet from the lathe

And most importantly the mig & plasma were not used for around a month prior to the damage yet the lathe was on several occasions without issue.

therefore ruling out any damage being pre existing or caused by the other machines

Tony

Edited By Antony Powell on 26/04/2017 10:32:19