559.9 Stroboscopic Effects

[ianmacd]

How so? They will be more than suitable for the environment just not suitable for how the environment is being used.

It will not have always been in the regs so at most its a code 4.

 

[Risteard]

It will not have always been in the regs so at most its a code 4.

A lot of things weren't always in the Regulations. The 1st Edition was four pages long. I don't see that as being relevant.

If it is dangerous (which I think it is clear that it is) then it must be coded accordingly.

 

[ianmacd]

A lot of things weren't always in the Regulations. The 1st Edition was four pages long. I don't see that as being relevant.If it is dangerous (which I think it is clear that it is) then it must be coded accordingly.

How is it electrically dangerous? Exposed live condutor maybe? Lets face it, there is nothing electrically unsafe with it at all. What would you say if it was an office instead?

 

[Risteard]

How is it electrically dangerous? Exposed live condutor maybe? Lets face it, there is nothing electrically unsafe with it at all. What would you say if it was an office instead?

I didn't say that it was electrically dangerous. I said it was a non-compliance which gives rise to danger.

Where does it stipulate that the danger must be from an accessible live part?

 

[ianmacd]

Its not compliant, that gives rise to a non-electrical danger therefore a code 4.

Whats the title for BS7671 you are getting the regs from?

 

[Risteard]

Its not compliant, that gives rise to a non-electrical danger therefore a code 4. Whats the title for BS7671 you are getting the regs from?

The Regulations are concerned with safety. This does not mean only danger arising out of electric shock, fires etc.

Code 4 states that it is not necessarily unsafe. Having a motor appear stationary is very definitely unsafe.

 

[NozSpark]

IMHO I don't think that this is within the scope of BS7671.. If you feel that it is a problem (which it is) then you should bring it to the attention of the site operator / owner in the form of a letter, this kind of think really comes under the site H&S risk assesment!

 

[Badger]

but wouldnt you hear the thing / machine working if it was running anyway, i certainly would, why dont you put a red light on the top flashing type beacon to warn the machine is switched on and running better still why dont you add an audible sounder at 200 db as well as the disco effect :^O :^O :run

 

[Risteard]

but wouldnt you hear the thing / machine working if it was running anyway, i certainly would, why dont you put a red light on the top flashing type beacon to warn the machine is switched on and running better still why dont you add an audible sounder at 200 db as well as the disco effect :^O :^O :run

You would likely be wearing ear defenders.

 

[Evans Electric]

PC , if there are no stroboscopic effects at the moment then I don't see the need to get involved TBH . If you are concerned , just make an observation that should stroboscopic effects be observed then the lighting should be upgraded to HF.

I have seen this occur on a lathe years ago , the solution then was to change the fittings to lead and lag , they don't do them now.

On a three phase supply the fittings are connected alternately R-Y-B for that reason.

I must say there are many small workshops with single phase lighting .

 

[kme]

I think I would agree with Lee here - and refer to:

131.1 (opening para.)

132.1(i)

133.2

133.4

I`d code 2 it, IF a rotating part appeared stationary when, in fact, it was not - and the above regs would be my reason for doing so (and 559.9).

KME

 

[ianmacd]

I think I would agree with Lee here - and refer to:131.1 (opening para.)

132.1(i)

133.2

133.4

I`d code 2 it, IF a rotating part appeared stationary when, in fact, it was not - and the above regs would be my reason for doing so (and 559.9).

KME

And you can prove that all those regs (most of which are not applicable due to no harm coming to anyone by the electrical system) are only applicable to new installs not existing installations being PIR'd. As I said before, code 4.

As said before, its a HSE issue not an electrical issue but should be flagged to the owners.

 

[Sidewinder]

Sorry KME would disagree, IMHO you are straying outside the remit of 7671.

The legislation controlling this would not be EAWR it would be PUWER.

The wiring regs wrt existing installs cannot reasonably be extrapolated to cover every eventuality.

I do not believe that this is a 7671 issue.

It is a safety issue that is caused by the installation, but it is not really such a problem.

First the machinery will be motor driven, it may be run by vsd's

A 2 pole motor will run at around 2880 rpm, a 4 pole around 1470, a 6 pole, 8 pole etc. slower.

Due to the slip in an asynchronous motor they will never run at synchronous speed as they have zero torque at this point.

50Hz is 3000 rpm. The likelihood of getting a standard woodworking machine running at exactly this is remote. The original designer would have had to select or design the drive train to increase the speed of the motor to exactly 3 krpm, doubtful been there and done that, it is not that critical.

A vsd/inverter etc. driven machine may run at exactly 3krpm.

I would be more concerned about external influences BE2, and a few others which I can

 

[kme]

I shall bow to thee superior knowledge in this field - I just provided my "gut instinct", as it were :coat

:C opcorn

GuinnessGuinnessGuinnessGuinnessGuinness - hic.

shee yoush aftersh - :x

 

[davetheglitz]

Out of curiosity does an HF fitting solve the problem? Is the HF effect a harmonic of 50Hz or is it free running? I don't know how they work!

If all in sync or just one fitting only provides the lighting for a machine - the strobe effect would now occur at a higher machine speed.

Perhaps we've found a good reason to keep 100W filament lamps!

 

[Sidewinder]

KME, no need for the coat, I ain't looked up your regs ref's yet!

Open debate & all that, I value your ideas.

Have one of your own on me!

Guinness

 

[davetheglitz]

Another quick thought - all very well thinking of the motor speed for various pole motors - but this doesn't account for gearing and no of teeth per inch of saws. There is a chance for the strobe effect regardless of frequency. Gut feeling is that the higher the frequency the less chance of a stationary effect - but not sure!

 

[davetheglitz]

Having said that I've just re-read Sidewinders post - and I think it's been covered. Nice post!

 

[Andy™]

frequency doesnt always help. if you have something rotating at 10 RPM, then a frequency of 10, 20, 200 or whatever could still make it look still, or moving slowly.

just look at car tyres on a TV

 

[Sidewinder]

Harmonics you mean

Please remember wood machining is quite high speed, 3k, 4k5, 6k, 9k rpm etc.

Linear speeds of bandsaws are also quite high and the chances of the rotating bandsaw wheels & blade both being at the frequency as the mains is almost impossible.

It is too late to quote acutal figures.

:Y

BTW, wood working machinery & facilities is the majority of my turn over, mech, hyd, pneu, elect, electronics, ****ing & H&S.