Posted by Neil Wyatt on 25/04/2017 23:06:04:
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
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