LED lighting and rotating machinery

[RF Lighting]

Following on from EddieM's workshop thread, and not wanting it to go off on a tangent !

I'm in the process of rewiring an office and when it's complete it will be lit entirely by LED.

The way things are going, I think this will become the norm.

I look after a large factory who are steel fabricators and manufacturers of ballistic and bomb resistant doors and windows. Whenever one of their 400W low bay SON fittings packs up we are replacing them with a 200W LED low bay.

This got me thinking about lighting in machine shops, both your domestic garage and industrial factories with rotating machinery, and the stroboscopic effect.

Is there any information available about whether they are suitable for use in this sort of environment, or if a capacitor could be added to make them into lead / lag fittings like the old wire wound fluorescents?

 

[bernardgreen]

A lot of LED lighting units produce light as a series of pulses of light and as such these lighting units carry the risk of stroboscopic effects on moving objects and rotatng machinery.

Low cost units often are made in such a ( cheap ) way that they create pulses of lightat 50 or 100 pulses per second due to the minimum cost driver being nothing more than a capacitor limiting the current through the LED element(s). These will create stroboscopic effects and the hazard associated with that effect.

Better quality units will have some form of pulse width control of the current through the LED element(s) and these units are likely to be pulsing light at 1000 pulses or more per second. These may create stroboscopic effects on some high speed machinery.

LED lighting where the LED element(s) are supplied with constant smooth DC current ( the elements NOT the assembled lamp ) will not produce pulsed light and therefor no stroboscopic effect. This could be pulse width modu'ated current but with smoothing circuitry between the PWM current control and the LED element(s).

Some LED lighting is a LED element emitting Ultra Violet light which excites a phospher to produce visible light. When a suitbale long retention phospher is use the pulses of light are smoother out by the phospher

With low frequency flourescent lighting it was common practise to fit an incandescent lamp close to the rotating machinery to provide some none strobing light to ( help ) ensure rotation could be seen.

Is there any information available about whether they are suitable for use in this sort of environment,

Reputable manufacturers would provide the information about the pulse rate and, if applicable, the phospher retention of the equipment they produce.

 

[ericmark]

When I worked in a factory we had a rev counter which worked by sticking a bit of light reflecting tape on the pulley, I found this would show 6000 rev per minute if pointed at a magnetic ballast fluorescent but would flit everywhere with a HF ballast it could not read that high. I found this a quick and easy way to check no magnetic ballasts were fitted in the machine shop area.

I would think it is likely the factory where you work has one it is a standard bit of fitters kit. Very little rotates at over 6000 rev per minute so if it will not read the revs likely it uses a PWM chip so is OK, since every lamp has it's own PWM chip unlikely they will be in sync it is only the units using capacitors to control current you are worried about.

In the main cheap LED lamps are around 70 lumen per watt and PWM around 100 lumen per watt, since designed to replace discharge lights which are very good to start with it is unlikely that they use cheap control methods.