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Flourescent Lamp Dimming

J

John Herbert

Jan 1, 1970
0
Does anyone know if fluorescent lamps can be controlled, dimmed in any way.

I have been asked to dim some lighting at my local hall and notice they are
fluorescent lamps.

Any info welcome thanks

John
 
V

Victor Roberts

Jan 1, 1970
0
Does anyone know if fluorescent lamps can be controlled, dimmed in any way.

Yes, most types of fluorescent lamps can be dimmed with the proper
control gear.
I have been asked to dim some lighting at my local hall and notice they are
fluorescent lamps.

Please post the lamp type number and we may be able to provide more
help with locating dimming gear. They will be much more expensive than
non-dimming gear, so some here may suggest alternative solutions that
do not require dimming gear.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
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C

Clive Mitchell

Jan 1, 1970
0
John Herbert said:
Does anyone know if fluorescent lamps can be controlled, dimmed in any
way.

I have been asked to dim some lighting at my local hall and notice they
are fluorescent lamps.

Ooh! This subject gets beaten to death on this list regularly.

The basic gist is that you need special ballast's to achieve proper
dimming. Some require a continuous feed and a dimmed feed, while some
just require a dimmed feed and others take a 0-10V signal directly.

All very expensive.

The reason for the special gear is that the electrodes at the end of the
tubes need to be kept hot to make them work properly and prevent
excessive flickering and tube damage.
 
V

Victor Roberts

Jan 1, 1970
0
There is an easier solution than the 2 replies below, but it is more
limited in what it will do. Simply supply the fls from a variac. I've
seen this done with a mixed install of filament and glowstart fl, and
it worked well. Lights were faded down successfully (the fls went down
to below 50% then blacked out) and also faded up acceptably, if not
well (filaments providing a good light level before the fls lit, thus
avoiding the usual unpleasantnses of fl starting). While to the
technical among us it was obvious that fade ups were not ideal, the
public normally noticed nothing amiss.

Operating glow start (a.k.a. switch start or pre-heat) or instant
start fluorescent lamps at 50% of rated power will greatly reduce
their life since these modes do not provide external electrode heating
power,

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
 
V

Victor Roberts

Jan 1, 1970
0
Victor Roberts wrote:

If run that way for long periods, yes. If the system is just used to
provide a soft fade upto full and down to off, no.

NT

I thought the OP wanted a solution for long term dimming.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
 
J

JM

Jan 1, 1970
0
quoting:
I thought the OP wanted a solution for long term dimming.


Actually you can make a dimming ballast out of a preheat ballast, series
type. Just get rid of the stater and provide cathode heat from another
line to low voltage transformer connected to the electrodes. Now you can dim
the series inductor while leaving the cathode heater on full power.
 
V

Victor Roberts

Jan 1, 1970
0
Actually you can make a dimming ballast out of a preheat ballast, series
type. Just get rid of the stater and provide cathode heat from another
line to low voltage transformer connected to the electrodes. Now you can dim
the series inductor while leaving the cathode heater on full power.

You certainly can, but this is no longer a preheat ballast. It is a
custom-designed line frequency dimming ballast.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
 
J

John Herbert

Jan 1, 1970
0
I would like to thank all of you for your advice.

I am indeed looking for a long term dimming solution. I have spoken to the
guy to find out exactly what he wants. He wants to be able to control the
fluorescent lamps from a lighting control desk, as they have theatrical
groups using the hall. I have given my thoughts, via your advice to him,
but I think it will not get off the ground because of the costs involved.

I would like to thank you all once again.



John Herbert



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C

Clive Mitchell

Jan 1, 1970
0
John Herbert said:
I am indeed looking for a long term dimming solution. I have spoken to
the guy to find out exactly what he wants. He wants to be able to
control the fluorescent lamps from a lighting control desk, as they
have theatrical groups using the hall. I have given my thoughts, via
your advice to him, but I think it will not get off the ground because
of the costs involved.

In that case, depending on access to the ceiling or roof, you may be
able to add another circuit of basic halogen floodlights. These would
provide the auditorium lighting during stage performances and could be
gently dimmed as desired. The existing fluorescent fittings would
remain as normal functional lighting for other events.
 

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