¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. TekScopes
  2. Messages
Single Messages Topics Expanded Polls

Re: Stopping Lights from Strobing

 

This might have been off topic, but nonetheless interesting reading. I
have been switching to LED lighting for about 4 years. My new lab and shops
are 90% LED. I am impressed with how much light the integral 20w
rectangular fixtures put out. The light is focused downward and lends
itself well to bench work. I also have about 20 solar LED lights around
the house outside, some motion sensitive, others just lighting walkways.
They are a win win over the old wired outdoor lighting. Every trip to the
US i bring back more, as the quality improves, and to use as practical
gifts here. In rural Mexico some old timers still use incandescent bulbs
all night long around their homes.. Energy usage consciousness is catching
on among the youth fortunately. And LED bulbs are dropping in price here
too but are still not an option for someone who earns less than $20usd a
day. Since the power grid here is government run, and residential power is
subsidized I'm hoping they finally "see the light" and subsidize LED costs
to make them affordable enough to become common.

Along with lasting longer and being less $ to run, they certainly have to
be better for the environment than mercury based lighting. I wonder how
much mercury based lighting actually is disposed of without release of the
Hg into the environment.. I do have a small cache of filament bulbs, mainly
for current limiters. I'm sure enough to outlast me.

Russ

On Saturday, July 14, 2018, Harvey White <madyn@...> wrote:

On Sat, 14 Jul 2018 19:31:28 -0700, you wrote:

Many years ago when I was a 'lecky, I worked on a very expensive lathe
light fitting that was using fluorescent tubes.

I was amazed that a lathe actually had a fluorescent fitting because of
strobe concerns but I found that the manufacturer "cheated" a bit for
safety reasons.
Fluorescent light fittings In most commercial use locations have power
factor correction capacitors fitted directly across the connection
terminals otherwise the power metering will not be correct & there can be
circulating current problems.
The manufacturer of the lathe fluorescent light fitting used a dual
fluorescent light fitting with two separate ballasts & only had a power
factor correction capacitor fitted to the one one fluorescent light.

The power factor correction capacitor caused a phase shift on the one
lamp compared to the other.
I actually ran the fitting with no power factor correction capacitors
fitted at all & with the one fitted & when the one capacitor was fitted
then the strobe effect was not visible.

I suppose that it may be possible to phase shift some LED lamps as well
with a capacitor if they use an actual iron transformer for the power
supply so you could have dual LED lamps set up in a similar way.

This makes the assumption that the standard triac/scr "give me part of
a phase" is what's being used.

If we have a situation where the AC is rectified, then chopped at a
high frequency for PWM, then we're not dealing with line synchronized
anything.

For the backlights I use in several projects, the PWM is on the order
of one Khz or so. What I have to do there is to worry about the
frame/field rate interactions.

Harvey




Regards,
Brian.





--
Good judgement comes from experience; experience comes from bad judgement.

99 times out of 10 a blown fuse is not due to a bad fuse.....
Join [email protected] to automatically receive all group messages.