Magnetic base LED machine light – WARNING MAY BE UNSAFE

[MWParticipant @mw27036]

Good on you, it's a great station. You kinda get a rough spectrum of all rock and few gems in between. Alice and the hairy bikers can be funny to listen to. Always depends on the tastes of the hosts alot of the time.

I actually listen to smooth extra also (because the signals bad on the main station) but i dont like to admit to it 😛

Apologies for the mini sidetracking. Conversation always leads elsewhere!

Michael W

 

Edited By Michael Walters on 01/07/2016 14:02:36

[Enough!Participant @enough]

Posted by duncan webster on 01/07/2016 12:42:49:

I found tat red wire went to -ve and blac wire to +ve, which wasn't a good start. Doesn't actually matter as long as it's wrong both ends, which is was, but I've made it right.

Exactly what I found with mine! At least they're consistent. ISO9000 (or whatever) would be proud of them.

[SillyOldDufferModerator @sillyoldduffer]

Posted by duncan webster on 01/07/2016 13:50:06:

Posted by SillyOldDuffer on 01/07/2016 13:04:15:

Posted by duncan webster on 01/07/2016 12:42:49:

Hi Duncan,

…

I wonder if you might need in-line fuses on both plus and minus? Depends on your stepper motor supply, which could be floating, or negative ground, or positive ground.

The extra fuse isn't a safety feature – it further guards against the possibility of a short damaging your stepper motor supply. (Perhaps!)

Dave

…

Anyway, I don't know whether my power supply is earthed on the LT, but I know it's isolated (I made it). I can easily earth one side of the LT winding on the transformer. Is this the right thing to do? Seems to me that if it's floating I can't get any leakage to earth. There is already a big fuse to limit current from the power supply, I was just going to put the fuse in to protect the LED wiring, not me, I think I'm reasonably safe at 40v

Edited By duncan webster on 01/07/2016 13:51:10

Hi Duncan,

Your modification pretty much eliminates the mains risk inherent in the lamp as bought and I'd be happy to use it as is. So we're only worrying about the possibility of a low voltage short in the goose-neck if your lamp happens to have the same fault as suspected in MikeP's unit.

Where the fuse or fuses go depends on how your 40V stepper supply is configured. If you have a voltmeter, all you need to do to find out is to check if there are any volts between the machine ground and the plus and minus 40V stepper power wires.

If the 40V+ wire shows volts relative to machine ground, you need a fuse in the positive wire.

If the 40V- wire shows volts relative to machine ground you need a fuse in the negative wire.

If both + and – shows volts relative to machine ground, you need a fuse in both wires.

If neither shows volts relative to machine ground, the one fuse should be fine.

Does the Duffer know what he's talking about? My understanding comes from a lifetime interest in Amateur Radio where there are different earth requirements for Radio Frequencies, Mains Safety, lightning protection and signal isolation. Professionally I know a bit about electrical practice in computer rooms and data centres but note all that's theoretical and not particularly deep. Therefore I'm quite happy to be corrected about the advice I offer – several people on the forum are better qualified than me.

Cheers,

Dave

[Andrew TinsleyParticipant @andrewtinsley63637]

A while ago, I was responsible for buying sub assemblies from China, to go into our light sources. I requested several samples to supply to a CE "Test House". The Chinese manufacturer said "Why bother?. I can supply modules with any certification that you might require" On checking this statement I realised that I was being offered a CE mark on the product, without any testing being done!

So beware of any CE mark on Chinese products that are imported directly from China or Hong Kong!

Andrew.

[LimpetParticipant @limpet]

I can second that – our firm purchased a heat press from a so called reputable supplier the heater was 10a 240V – this heater had a centre tap with that cable cut off about 1/4" short of the metal plug with an earth cable connected to an isolated control box – the rest of the machine became live – I condemned the machine ended it's very short life in the bin CE just stood for China Export

 

Edited By Limpet on 29/11/2016 20:58:48

[Neil WyattModerator @neilwyatt]

Posted by Andrew Tinsley on 29/11/2016 20:30:41:

A while ago, I was responsible for buying sub assemblies from China, to go into our light sources. I requested several samples to supply to a CE "Test House". The Chinese manufacturer said "Why bother?. I can supply modules with any certification that you might require" On checking this statement I realised that I was being offered a CE mark on the product, without any testing being done!

So beware of any CE mark on Chinese products that are imported directly from China or Hong Kong!

Andrew.

A lot of 9oimported model engineering kit is CE certificated by the manufacturers properly, although I don't deny there is stuff that is just marked 'CE', especially cheap grey imports.

[duncan webster 1Participant @duncanwebster1]

My understanding is that it is the responsibility of the importer to do the CE compliance stuff, and he cannot sub it onto the manufacturer, see thread under LED fluorescent tubes

[Neil WyattModerator @neilwyatt]

Posted by duncan webster on 29/11/2016 23:22:17:

My understanding is that it is the responsibility of the importer to do the CE compliance stuff, and he cannot sub it onto the manufacturer, see thread under LED fluorescent tubes

It depends whether they simply import or they rebrand. If they rebrand, they need to have their own compliance file.

.Gov.uk says "If you are importing a product that is from a third country you have to check that the manufacturer outside the EU has undertaken the necessary steps. " which is basically checking their doumentation, not re-doing the compliance testing.

Edited By Neil Wyatt on 29/11/2016 23:53:22

[HopperParticipant @hopper]

Posted by Neil Wyatt on 29/11/2016 21:05:37:

Posted by Andrew Tinsley on 29/11/2016 20:30:41:

A while ago, I was responsible for buying sub assemblies from China, to go into our light sources. I requested several samples to supply to a CE "Test House". The Chinese manufacturer said "Why bother?. I can supply modules with any certification that you might require" On checking this statement I realised that I was being offered a CE mark on the product, without any testing being done!

So beware of any CE mark on Chinese products that are imported directly from China or Hong Kong!

Andrew.

A lot of 9oimported model engineering kit is CE certificated by the manufacturers properly, although I don't deny there is stuff that is just marked 'CE', especially cheap grey imports.

Even when done "properly" it only means the supplied samples were up to the required standard. As time goes on through the production run, "quality fade" is common Chinese business practice where materials and processes are cut back gradually gradually so they can make a profit on their low quoted production price. It's so common that whole books have been written on the practice. The Chinese, however, say it is not "quality fade" but "oversight fade" as Western customers turn a blind eye to quality as time goes on and focus only on keeping prices low.

[MuzzerParticipant @muzzer]

I'd better check all my laptops, routers, games machines, iPhone chargers, TVs, domestic appliances, audio equipment, light fittings etc, given that the vast majority are made in China. Without wishing to generalise of course.

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Hopper on 30/11/2016 08:00:19:

Even when done "properly" it only means the supplied samples were up to the required standard.

Not at all. The importer is responsible for ensuring that all relevant EU Standards are complied with on a continuous basis and for ensuring that the products are correctly marked. Of course things may change after Brexit and quality is likely to fall.

(Now ducking to avoid the flack )

Incidentally, I've seen many items which arrive CE marked but which are not subject to any Directive requiring CE marking. That is also an offence.

Russell.

[Author]

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