strobing

Warning: LED torches and cap lamps can cause a strobing effect that can make rapidly turning things like drill chucks and grinder wheels seem to be turning slowly or not at all.

Bill

Reply to
Bill Wright
Loading thread data ...

Yes they can. I think it has something to do with the fact they do not actually have any persistence of emission like most tungsten lamps would or like the coating on many discharge lamps. I think you would need to be very unlucky to get the strobe speed so near a rotation speed that it almost stood still though. Brian

Reply to
Brian Gaff

A useful tip, this was a well known issue in factories and workshops with fluorescent lighting but I'd not heard it before with LED lights.

Reply to
Ash Burton

It can be the case with mains powered LED lamps... the frosted glass type usually less so since they tend to run high frequency switching PSUs. The filament style sometimes just have the four filaments run in series with a rectifier - so they can strobe at 100Hz.

Battery ones ought to be ok, unless they are they type that uses a DC/DC converter to step up the battery voltage.

Reply to
John Rumm

Decent modern florries run at a much higher frequency than mains and don't give this effect. And unlike LEDs, the phosphors used have a degree of persistence, so tend to minimise switching flicker.

Reply to
Dave Plowman (News)

What can happen is that when the tool is on load it looks as if the wheel or chuck is slipping.

Bill

Reply to
Bill Wright

It is because a lot of LED torches use a high efficiency switched mode current drive power supply. A side effect is that the LED brightness is modulated at a moderately high frequency.

You can see it too on car brake lights and pelican crossings in your peripheral vision (the strobe rate on them is a bit low for my taste).

Reply to
Martin Brown

You use a torch to light work on a machine tool?

Reply to
Dave Plowman (News)

They do.

LEDs tubes are meant to get around this by using a similar coating but as yet I haven't tested this like I have with our labs florry tubes.

unless of course you can explain this

notice the can rate and the light on the monitors case and on the wall behind.

formatting link
iphone at 240FPS

formatting link
iphone at 60FPS.

Reply to
whisky-dave

The lathes in the basement had lights pointing at the work, especailly the the new digital one we had it did lok like a standard torch had been adapted like the older ones had what looked like adapted angle poised lamps.

Reply to
whisky-dave

Not here they don't. My definition of decent is different to yours.

Reply to
Dave Plowman (News)

Quite. But a torch by nature is a battery device. Why would you use a battery light on a tool driven by mains?

Reply to
Dave Plowman (News)

because that's why you call them a torch, torches are portable so are desig ned to work on batteries. If yuo;re using LEDs to illuminate an object that is coneceted to 'mains' then you would be unlikely to use DC to power the LED's

You might also come across other problems as the EU has a charter on poweri ng LEDs from tehr mains, but it seems Germany thinks it's excluded.

According to DARC, the current Federal Government policy violates internat ional law and the EU Charter.

from.

formatting link

specific product.

Reply to
whisky-dave

I bet you've never tried such a test, and what do you define as decent anyway. Of course my florry tubes weren't causing any problems either.

Reply to
whisky-dave

When my Dad had his lathe delivered in the late 70s (who do you think taught me the importance of the right tool for the right job ?) I remember the delivery guy commenting that we should fit something to the power supply to de-phase it from the lights. (Or maybe something to the lights). He had the mandatory tale of seeing someone put their face into a spinning lathe.

Does anyone remember those fancy record decks which had a strobe speed adjustment ? I had a brief smug moment when I bought (it may have come with a magazine) a printed disc which you could put on the turntable. It had markings to stand still at the 33/45 rpm mark.

Briefly smug, because as a friend pointed out, while I knew my turntable was out of whack, I had no means of adjusting it. (Insulating tape around the drive spindle was not a success :) )

Reply to
Jethro_uk

Yes, I still have one (haven't used it for about 25 years tho). Has a strobe built in an you can adjust the speed up/down. And set it for

60Hz if you happen to take it there. It's a Thorens TD135 II.
Reply to
Tim Streater

Now there's a name I haven't heard for .... over 30 years.

Wow, flutter and rumble :)

Reply to
Jethro_uk

My grandpa had various fluorescent tubes (full-length 5-foot ones on the ceiling and shorter 2-foot ones that plugged into bayonet fittings) illuminating his garage where he had his lathe, but he also had an anglepoise lamp with a low-power tungsten bulb to illuminate the work. I remember him telling me (and showing me) why the tungsten one was necessary, to avoid strobe-freezing. It also provided useful back-lighting and shadows which made the swarf a bit easier to see as it was coming off.

My dad's B&O turntable had those strobe markings - it had two scales, one for 50 Hz and one for 60 Hz mains. I was surprised how sharp the markings were - not much wider when rotating than when stationary, given that tungsten lights stay alight a lot longer than fluorescents on each mains cycle.

Reply to
NY

Oops, TD125 II sorry.

Reply to
Tim Streater

Garrard 401. I used to sell them.

Reply to
Bob Eager

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.