American Faceting Machine Testing?

[Deanoss]

Hey Guy's,

I had a client ask me last week if I do Pat testing and without thinking first I said yes! However some of the equipment he has is very old (40+ yrs) and American. I haven't agreed to do the job and I told him straight I would have to find out what is involved with testing them first or I can't undertake the job. If anyone has done these before or can shed a little light on it I would be grateful.

He has a faceting machine which is run from a transformer (110-120v)

 

[Wilko]

Thanks for the pics - I really luv the old gear - reminds me of my youth etc. I would spend much more than usual time doing visual inspections as its likely there will be some degeneration in kit this old. I would advise Customer that "I may need to dismantle some of it to confirm the wiring is still robust. And with kit this old it may not survive the operation" ... I'd be retiring that fine old transformer for a nice new yellow one as it's probably the critical safety bit. All the best, David.

 

[Adam W]

I don't know what a faceting machine is for but the principles of testing one would be the same as for any similar bit of equipment, eg if it's class 1 you need to test the earth continuity, you'll need to do an insulation resistance test, cables, plugs etc will need to be suitable for the voltage it's being used on.

I'd probably have the CoP handy when testing it.

 

[Deanoss]

Thanks for the pics - I really luv the old gear - reminds me of my youth etc. I would spend much more than usual time doing visual inspections as its likely there will be some degeneration in kit this old. I would advise Customer that "I may need to dismantle some of it to confirm the wiring is still robust. And with kit this old it may not survive the operation" ... I'd be retiring that fine old transformer for a nice new yellow one as it's probably the critical safety bit. All the best, David.

Hey David,

Thanks for the response, I'm glad you liked the pics, not everyday you get to work with machine's like this. I will follow your advice regarding th

Thanks for the pics - I really luv the old gear - reminds me of my youth etc. I would spend much more than usual time doing visual inspections as its likely there will be some degeneration in kit this old. I would advise Customer that "I may need to dismantle some of it to confirm the wiring is still robust. And with kit this old it may not survive the operation" ... I'd be retiring that fine old transformer for a nice new yellow one as it's probably the critical safety bit. All the best, David.

Hey David,

Thanks for the response, glad you like the pictures, it's not everyday You See these machines. I'll definitely recommend and new transformer and see how the client feels about a full inspection of the machine. It's a shame because he is only taking it out of his house for a one day exhibition but unless it has been tested they won't allow it onsite.

 

[Lucien Nunes]

Why would you change the transformer? In the UK we are used to 110V equipment being 55-0-55 CT-E and not suitable for direct connection to the mains. This machine was designed to be connected directly to the (110V) mains and the transformer is only needed because our voltage is wrong. In a sense the transformer becomes part of the machine to make it work on 230V, not an electrically separated safety source of power. If the transformer were inside the machine (and many machines do have a stepdown transformer built in) would you think of opening up the machine and changing it?

Now it may be that the insulation of the machine is poor and that is a different matter, but it might not be a great idea to sweep an insulation problem under the rug by connecting it to a 55-0-55 CT-E supply and saying 'well the insulation isn't so important now! Indeed a yellow tool transformer with CT-E output might not be suitable, as this requires double-pole fusing wherever fusing is used. If the machine has internal fusing it will probably be in the line only (as it was intended for 110V with earthed neutral) and so the transformer would need modifying to 0-110 and marking as not for tool use, etc. All in all a bit of a bodge rather than an actual solution to inadequate insulation.

The only other reason I can think of for changing the transformer would be if it is auto-wound (although it doesn't look like it from the label) and the machine insulation is only adequate for 110V. With an autotransformer, provided the common terminal is the neutral, no part of the machine would be over 110V to earth; but if the supply polarity is reversed it could be that the machine is slung between 230V and 230-110. The machine would work fine but would require insulation good enough for 230V.

Re PAT testing, the visual is important a) because of deterioration and b) because it was built to different standards and may have class 0 insulation etc. The earth continuity would have to be checked to the transformer case and machine itself if class 1. If the transformer is isolating, then an insulation test from the plug would only test its primary, in which case disconnect the machine from the transformer and test it separately at 250V, and test the transformer primary with one end of the secondary earthed (obviously don't do that if auto!)

To put it in perspective, compared to a lot of the stuff I work with daily, this is neither old nor obscure. I have older pieces of equipment in use in my lab that I wouldn't even think of as old, also lots of 110V gear running on transformers, mostly autotransformers from the 1960s-70s. The oldest kit I routinely subject to 'normal' PAT is 80+ years old and it is mostly fine, provided one appreciates the specifics of its construction and the difference between a non-compliance with current standards and an actual hazard.

Inspect closely, consider the specifics of the transformer winding arrangement, scrutinise the insulation and apply common sense.

 

[Deanoss]

Thanks Lucien for the response, I felt out of my depth with this type of equipment as I have not come across a machine like this before. Your information will be most helpful, cheers