Moving Yoke for Light House

[thelightguy87]

I'm working on a show called "The Foghorn" It is inside a lighthouse and we are looking for a practical rotating light fixture. we also own a few Robe Color Wash 575AT fixtures. In a production meeting about this, it was asked from the director who is unfamiliar to lighting technology, why can't the light make continuous rotations. I thought about it, and although I've not torn a moving yoke fixture apart entirely, so i don't know what physically stops it, I didn't have an answer for him. I thought maybe it was wires, then i thought it would be able to feed wires through the yoke. And since the fixture can already do a 540 degree rotation, can anyone explain whats stopping it, and or why it can't just continuously rotate? My last guess is a way of tracking the position, having a stop point, so you can tell where the fixture is in comparison to its home location.

Also, does anyone know of a fixture that CAN make continuous rotations?

Thanks

[Sayen]

If it's a set piece and doesn't have to be very bright, what about a cheap DJ light? I don't know specifics, but I've seen a few that just swirl endlessly.

[drawstuf99]

I've seen some of those rotating beacon lights that are quite large and powerful--not your average "party store" beacon light. Maybe take a look at those if that's the direction your leaning towards?

[gafftapegreenia]

I think you are over thinking this. Unless it has to be extremely bright, your stage is huge, or change colors, I don't see a need for a moving light.

First, all traditional lighthouses lenses are just huge Fresnel lenses. A suitable look-alike could be something like this: Revolving Beacon for Lawn Lighthouse Either the first or second item on that page has plastic "bulls eye" (step lenses) lenses that look like enough like fresnels to work.

The other option is a cheap DJ light. However, those use rotating reflectors, and while that works, it won't have the "realistic" look. They also rotate a lot faster than a more traditional lighthouse beam.

Some lighthouses didn't even have rotating optics, but rather flashing lamps. Unless it must rotate, there is always that option too.

My imaginative side tells me that three, 6" or 8" (or larger!) Fresnel lenses could be attached to a rotating platform with a lamp in the center.

My last idea is to get the standard in rotating police beacons for Broadway shows and the like. the Mark 12. Any respectable rental house should have some available.

[drawstuf99]

The Mark12 above looks almost exactly like what I saw used. You can control the speed and intensity.

Surely it wouldn't be that hard to wire up a small, low voltage motor (this is assuming you know what you're doing and have some skill in electricity) to some wood and bolt a fresnel-like fixture to it.

Think about how you're treating what this fixture is incased in, too. Is it slightly diffused, fogged up? Or, is it clear as a every-day window? If it was fogged up--say, if it's during a storm scene or something--it would probably look the same to have a beacon light as a slightly more complicated fresnel light.

[thelightguy87]

the reason i asked about the moving light is because thats what the design staff specifically wants to use because we already own them, and the speed/intensity and such can be controlled via console. I'm co designer for this show, so i'll mention to my partner our other options and then see what the staff thinks. We would be using a wash fixture so it would have the fresnel lens, and possibly modifing it more, we talked about putting a clear case on the outside with large fresnels lenses on the outside, to appear to be a larger lamp. But i had issues with that because i didn't want to strain the motors in the fixture with extra weight. the light house is pretty big so we need a light source to compliment its size. but i made notes of all your ideas and will bring them up in the next meeting.

thanks

[Pie4Weebl]

in the neck of the unit there is a physical pan stop piece which catches it at the end of the rotation, it is not something you want to mess with. The unit homes off it these two pan stops and every position it can hit is relative to these two stops.

We just finished fixing a broken pan stop on a mover damaged by a certain municipal theatre group which won't be named. and it was a total pain.

[BillESC]

The simplest answer is to get a display rotator with a PTO and mount a fresnel to the top and let it go.

[soundman]

Not to mention just stopping it for homing tracking purposes the had stop also prevents the wires for twisting up too much and getting damaged.

If I were you I would build a custom fixture for it with a lamp that is stationary and lens that rotate.

[soundlight]

As has been mentioned - a regular moving yoke fixture cannot move in continuous rotation for a few reasons: 1) hard stops and calibrations. This is how the fixture homes itself and determines where it is. 2) Wiring harnesses. Most moving lights, to the best of my knowledge, do not use brushes at the yoke and tilt positions, so they are not able to spin continuously or else the wires will twist too much and either stop the fixture, break the PCB, break the connectors, or rip themselves.

The moving light that I know of that can complete continuous rotation is the Morpheus Panabeam XR2, which can spin in continuous motion in both axes of movement.