Re: [photo-3d] Re:projector brigthness

["John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>]

> Is there any information/drawing available describing what additional
> components are needed to supply the required voltage and current? A
> simple transformer(s) dropping the 120 vac to 24 vac, having the proper
> wattage capability OK?

For A.C. applications, usually this is sufficient.  Make certain that the
transformer current (amperage) rating is high enough to handle the wattage
of the lamps at their specified voltage.  A rating a little bit greater than
the requirement is a good idea, as the transformer will run cooler and safer
(although it will be a bit larger and more expensive).  Make sure that you
include a fuse or circuit breaker of the correct rating in the circuit.  The
original fuse or breaker will probably be incorrect and dangerous (not
tripping quick enough for the new, probably lower, current flow).

Another consideration is the sockets themselves.  Replace existing sockets
with ones intended for the specific new bulbs.  Do not use adapters in the
existing sockets.  These are okay for "reading lamps", but not for
projectors where precise filament location is important.

Also, for projection where the filament position determines light
distribution as well as brightness, the use of "Tru-Focus" or similar type
projection bulbs and sockets are recommended.  These insure that the
filament is always at the right height and perpendicular to the optical path
for maximum brightness and most even light distribution.

If there is room in the lamphouse, you might want to consider lamps of the
type that have built-in reflectors.  These are usually more efficient than
those that rely on a separate reflector.  If you do choose to use a separate
reflector, make sure that it is of sufficient diameter and the correct
radius and distance for the filament size of your new lamp.  Also, similar
considerations must be applied to any condenser lenses in the system.

Cooling must also be considered.  Halogen cycle type lamps are smaller and
much more temperature sensitive.  With conventional non-halogen lamps, all
you have to be concerned with is that they do not get too hot.  With halogen
bulbs, they must reach a certain temperature (specified in the data sheet
for the specific lamp) before the halogen cycle will work.  Too cold and
they will age and blacken like conventional lamps.  Too hot and KABOOM!
Best to have an expert design the new cooling system.

JR


 

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