Light Controller-Stroboscopic effect

This is one of the reasons that strips of fluorescent lights MUST be run from separate phases of the mains supply and not all from the same phase...

If all the lamps were on the same phase then the machinery could appear to be stationery when its not so this is one area of health and safety that is very strictly enforced.

It would be far better to use a fixed or purpose designed stroboscope for this application so that the operators know the dangers of seeing something stationery when in fact its moving...

John.

Could you try with a high frequency fluorescent lamp ? The steel strip is slower speed than 12M/min when it was coating . Maybe this will solute the problem. otherwise you try to use a bulb powered by rectifier?
In fact there are many kinds of lamp choosed fro the purpose. I think.

I believe that your understanding of the stroboscopic effect is incorrect; the "motionless" appearance is fine for repeating events, but useless for something like a continuous coating. It would only work in your application if there is a repeating flaw with a suitable distance / travel time interval. And while it is true that a single flaw progressing through the inspector's view will "blink" under strobe lighting, so will everything else. Renting or borrowing a conventional stroboscope for a few days should confirm what it can and cannot do for you.

Is it possible to consider use of video or other sensing means in place of human inspectors? Let the human be the judge as to whether the flaw is acceptable, reworkable, or scrap as the sensors discover it. If this cannot be done, consider moving the light so as to provide a reflection of it [from the coating] to the inspector; surface flaws are often more noticeable that way on smooth surfaces.

Ron and All,

Thanks for the idea. I understand about stroboscope, moreover about its etimology. And that is why I expose this to others hoping a way out.

Do you know one of vendor experience in the designing and installation of those such a light management system? I think HF ballast will be my choice.

And thanks too, about safety. I will assess and make a potential problem analysis.

Regards.

Abu Khansa

Here's another thought. If the strip speed is as low as 12M/minute, as someone above mentioned, then I wonder if simply snapping a digital picture every 2 seconds of a .4M segment sould make sense. Then the operator would only need to view a monitor and would have time to focus on a possible defect.

But can the strip speed really be that slow?

Dear Ken and All,

As you knew that the issue of 12M/minute was first come up by the idea from cnpower, and I don't have any idea where that numbers came from. But I my self didn't indicate any signs about speed, so let me get it straight, the line speed are varied from 50 mpm to 150 mpm.

Logically no stroboscoping is needed to the speed of 12 mpm, because you can imagine both the distance of 12 meters and the time of 60 seconds.

So please set your mind of views to the 150 mpm!

thanks and regards,

Abu Khansa

Another thought. Many years ago (1980's) I worked in an electronics plant in which circuit bords were analyzed for missing components by a video camera and pattern recognition software. Then, perhaps one board per second was analyzed. Now, imaging and computing speeds are thousands of times faster, and detecting a defect would be an easier task, providing the coating is not entirely random. A jet sprayer could mark the edge of the sheet at each defect, and a subsequent inspector could focus on just that area.

I'd second Ron and Electroman's answers. The inadvertent stroboscopic effect that makes synched machinery appear stationary is a serious safety hazard. A designed-in strobe effect would require loads of shielding, guarding, etc. to prevent other things in the area from appearing stationary, and to limit hand (etc.) access to any stationary-appearing parts. If the strip is moving at high speed, then the strobe rate would have to be high speed too, and its vaue would decline. On the other hand if the strip moves slowly, then a slow flash rate might draw attention to flaws as they jump across the field of view in perhaps four or five steps.

This is completely unlike strobing a rotating assembly to make it appear motionless for a relatively long period of time, to inspect a chip on a circular saw blade for example.

hey guys/gals i have a way of reducing stroboscopic effect which is an end result of variation in the frequency of the input i.e., intensity of the light varies with the frequency of the input hence you can use an oscillator which gives constant frequency output........ suggest me if im wrong