Strobe Lights.

The "flickering" is what makes the blades appear to stop. If the light flashes when the blades are in exactly the same position they were in the previous time the light flashed, you will not perceive that the blades are turning.

This can be a safety hazard when machinery running at certain speeds is illuminated by fluorescent lights - the on and off of the fluorescent bulb with every cycle of the AC voltage can make the machinery appear to be stopped (yes, I know it's a simplified explanation).

John

On 2/8/2009 4:06 PM snipped-for-privacy@webtv.net spake thus:

Sure: how fast can you blink your eyes?

-- Personally, I like Vista, but I probably won't use it. I like it because it generates considerable business for me in consulting and upgrades. As long as there is hardware and software out there that doesn't work, I stay in business. Incidentally, my company motto is "If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

Spin yourself at the same speed as the fan.

It just occurred to me that the strobe lights and circuits take a finite amount of time to charge ! and discharge very quickly to give the flashing strobe effect.

It also occurred to me that superbrite white LED's should fire very quickly so by using a 555 timer and an appropriate driver would give you a quick strobe ! Without that recharging delay !!

I will have to try this on my testbench soon !

Yukio YANO

On 2/8/2009 7:44 PM Yukio YANO spake thus:

Could work, would be interesting, but wouldn't be able to touch a xenon tube for brightness.

Nothing new. You can pulse to the LED's peak rating. The longer the pulse the brighter it appears.

You could also use LCD glasses to view the fan.

greg

Turn off the fan. The blades will be clearly stopped.

I work on and do tune ups on my own vehicles.I know about using an auto strobe/timing light.

When I was watching that How It's Made tv program, I figured it would be ''cute'' if the rotating fan blade on my old antique electric table fan could appear to stop rotating.That is what the How It's Made program showed on tv.I still think it is a ''cute'' idea though. cuhulin

Just keep it away from kids.

greg

I like those Western movies, when the wagon wheels look like they are running backwards. cuhulin

On 2/9/2009 1:10 PM snipped-for-privacy@webtv.net spake thus:

They were. Didn't you know they shot all action scenes backwards back then?

You can imagine how hard it was for all them actors to learn to talk backwards.

-- Personally, I like Vista, but I probably won't use it. I like it because it generates considerable business for me in consulting and upgrades. As long as there is hardware and software out there that doesn't work, I stay in business. Incidentally, my company motto is "If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

On Sun, 08 Feb 2009 21:44:46 -0600, Yukio YANO put finger to keyboard and composed:

I have a Ministrobe kit designed by Electronics Australia in August

- Franc Zabkar

Sure. Turn the fan off.

Grab it.

It is 70 degrees outside right now.The old antique Hunter electric fan on the end table by doggy's end of her couch is running. cuhulin

Stick your nose in it....

jak

Outch! cuhulin

We used to have a tuning fork with a peep hole between the forks to time teletype motors. You tap the fork and look through the peep hole and the dots on the teletype motor would stop when the right speed was set.

So yes, you can use tuning forks or an electronic vibrator with a peep site.

Way way back when I repaired washing machines for a living, Hotpoint supplied a cardboard disk which fitted over the centre nut of the drum pulley, The disk had a ring of dots which appeared stationary under incandescant light when the drum was turning at the correct distribute speed - which was critical.

Ron