Fluorescent ballast + dimming & machine tools
Posted by
Multi-Volti Devices
on 2001-09-18 01:45:58 UTC
Hello:
Fluorescent lighting and dimming is not common.
If they are magnetic ballasts (big heavy inductors), the only practical way
to dim is with a series capacitor - and this is beyond the average person's
design skills - because of the ac line voltage, a pretty rugged capacitor is
needed, and each ballast is designed for a specific lamp, which has a
nominal current rating - this info was hard enough to find when I was a
ballast designer, let alone 'on the street'. Then there is the question of
whether or not they use starters.
If they are electronic ballasts (they will either state that on the cover,
or will be noticeably lightweight compared to magnetic ballast (which
requires previous ballast lifting knowledge base!), dimming can be
accomplished by a handful of techiques, usually proprietary to a specific
manufacturer's design.
So, I don't think there's a simple answer regarding dimming for
fluorescents. If they are dimming ballasts they will almost definitely say
so on the case...probably with warnings so you don't plug any low voltage
control wiring into 120 vac (some dimming ballasts use 10VDC control
circuit)
Email me the case info (everything you can read on the ballasts (which means
popping the cover on the fixture), and maybe I can help you figure it out.
Magnetic ballasts are weird...and an occasional one with weird wiring will
pop up.
To make this reply relevant to the list, some literature advises against
using fluorescent lamps in machine tool environments because at a specific
rotational speed, moving machinery can appear stationary due to stroboscopic
effect (50-60 Hz ballasts), which (according to the literature) increases
the risk of injury (I guess that would require hearing impairment too, if
you don't hear the machine running and stick your hand into something.
Electronic ballasts drive the lamp at typically 25-50 kHz for about 15%
higher light output and elimination of the stroboscopic effect...safer with
machine tools.
Finally - something I can contribute to the list -unfortunately pretty
trivial.
Murray
Fluorescent lighting and dimming is not common.
If they are magnetic ballasts (big heavy inductors), the only practical way
to dim is with a series capacitor - and this is beyond the average person's
design skills - because of the ac line voltage, a pretty rugged capacitor is
needed, and each ballast is designed for a specific lamp, which has a
nominal current rating - this info was hard enough to find when I was a
ballast designer, let alone 'on the street'. Then there is the question of
whether or not they use starters.
If they are electronic ballasts (they will either state that on the cover,
or will be noticeably lightweight compared to magnetic ballast (which
requires previous ballast lifting knowledge base!), dimming can be
accomplished by a handful of techiques, usually proprietary to a specific
manufacturer's design.
So, I don't think there's a simple answer regarding dimming for
fluorescents. If they are dimming ballasts they will almost definitely say
so on the case...probably with warnings so you don't plug any low voltage
control wiring into 120 vac (some dimming ballasts use 10VDC control
circuit)
Email me the case info (everything you can read on the ballasts (which means
popping the cover on the fixture), and maybe I can help you figure it out.
Magnetic ballasts are weird...and an occasional one with weird wiring will
pop up.
To make this reply relevant to the list, some literature advises against
using fluorescent lamps in machine tool environments because at a specific
rotational speed, moving machinery can appear stationary due to stroboscopic
effect (50-60 Hz ballasts), which (according to the literature) increases
the risk of injury (I guess that would require hearing impairment too, if
you don't hear the machine running and stick your hand into something.
Electronic ballasts drive the lamp at typically 25-50 kHz for about 15%
higher light output and elimination of the stroboscopic effect...safer with
machine tools.
Finally - something I can contribute to the list -unfortunately pretty
trivial.
Murray