# New Clancy Power Assist



## SteveB (Sep 16, 2009)

Just a write up about our newly completed install of Clancy Power Assist and line shaft winch systems for our electrics.

Under a City of New York funding grant, we replaced the existing counterweight systems for our 5 primary electrics and 2 lighting ladder positions. The electrics use full length raceways (40ft.) and typically have 27 instruments (#1 thru #4 electrics), the #5 electric is a steel ladder truss pipe with Socapex cabling and has 12 L&E 6ft. MR16 MiniStrips, while the ladders - which have 3 - 30ft. horizontal rungs spanning the US/DS wing, have 24 ellipsoidals each. Our website shows the plot and ground plan – Brooklyn Center for the Performing Arts

Due to combined weight of the raceways, pipe and lighting units, the electrics had "married" arbors for the #1 thru #5 electrics and the positions were a b _ _ _ h to move, requiring 2 people to operate. The ladders were operating at the capacity limit of the arbor as well.

Thus the grant to update these systems. I believe our budget was slightly over $240,000, of which a HUGH chunk was electrical. No comments necessary about the costs of doing business in the City of NY, FOR the City of NY !.

Portion 1 of the installation was to have power run to our stage left counterweight rail position. We had a 100 amp, 3 phase service run, with individual fused switches located adjacent to each winch location, as well as controls on Stage Left & Right for the ladder line shaft systems. Note that the typical Power Assist winch draws 5.5 amps on a 120/208 volt, 3 phase system, so you do not have to have as much power local as we had run. In our case it was cheaper for the electrician to run 100 amps, as he was tying in to an existing 100 amp breaker, thus saved having to install a new panel and main breaker. 

The options then for the rigging system portion was Line Shaft winches, or Clancy Power Assist.

For those of you not familiar with the Clancy system, it's essentially a chain motor mounted to the floor where the bottom purchase line floating floor block sits in a standard counterweight system. The motor feeds a chain that attaches to the bottom of the arbor, feeds thru the motor and up to a segment transferring to a 3/8" aircraft cable in mid travel, with the cable moving over the head block and attaching to the top of the arbor. Thus the winch, chain and cable replaces the purchase line on a counterweight system. The capacity of the motor is 2000 lbs. The arbor(s) remain loaded with 1000 lbs of counterweight, but the overall capacity is 2,000 lbs. In operation, the counterweight on the arbor never moves and never needs additional or fewer weights. The motor can handle all the loading of the pipe, be it no load, or up to the 2,000 lbs system capacity.

In our installation, I.Weiss, the rigging company, had to replace the 55 year old arbors with newer Clancy arbors, as well as replacing all the electrics head blocks, loft blocks, aircraft cable and fittings, which added significant cost to the installation in terms of labor and materials.

Our ladder positions were updated with Line Shaft winches. These are essentially a horizontal pipe shaft (in this case running US/DS) with cable drums spaced accordingly, at one end is a motor that turns the shaft. It is my understanding the reason they used line shafts for the ladders was an issue resulting from the need for much mule-ing and fancy cable paths to assorted loft blocks, required to get the aircraft cable from the head block to the loft blocks, all of which were custom on the existing counterweight system. Thus the decision to place 2 line shaft winches. It is also my understanding that the Power Assist systems can be more cost effective to install as compared to a line shaft winch, and in our case the rigging company did not want to have to do a grid iron load analysis, which they would have had to do if they went to 5 additional full stage width line shaft for the main electrics.

In any case, the control heads are the same winch to winch, and consists of a box (4”x 8”x 8” high, approx.) that mounts where the rope lock had been mounted. The control system we opted for (Scene Control 50) does not have a central computer driven system, but does allow for recordable target positions to be set at each station, up to 4 positions, at any height located between the maximum and minimum limits. 

We used the main electrics last week for a tour of I Love a Piano, and again today when I re-rigged our ladder positions and hung the 48 ellipsoidals on the 2 positions. One cautionary note about line shaft systems is to never let the pickup cables go slack as the cable may skip a cable groove on the drum. This can foul the systems. 

If I had one nit-pick, it would be a request to Clancy to replace the “At Target” neon indicator light with an LCD screen that indicates which target you are at – 1, 2, 3 or 4.. Right now it's a guessing game, as the light is lit indicating you are at a target, just not which one. 

Other then that I can only say that it was a joy today to simply press “UP”, when finished. No continually shouting “Add 4 more weights !”.

Steve Bailey
Brooklyn College


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## Erwin (Sep 16, 2009)

I have had the pleasure to work with fully automated stages. It is a real treat! When it comes to the relatively low budget world of live theatre, however, these systems are beyond most peoples reach. Even if we could find the money to install a system like this at our theatre, we would likely be unprepared for the maintenance of the system. 

Thanks for sharing your experience, and enjoy pressing the "Up" button.


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## Footer (Sep 16, 2009)

Agreed on all of that. Your world changes drasticly when you no longer have to worry about re-weighting on an electric. I do like the idea of the power assist option. Its much better then the motorized head blocks that are still out there and still require you to keep everything in balance. Is this a single or double purchase system?


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## derekleffew (Sep 16, 2009)

See Theatre & Stage Equipment Products - Automated Rigging & Controls - PowerAssist for more information on what Steve is talking about.

While such an installation is initially expensive, the cost in labor-savings of not having to load/unload pigweights on arbors should pay for itself.


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## SteveB (Sep 16, 2009)

derekleffew said:


> See Theatre & Stage Equipment Products - Automated Rigging & Controls - PowerAssist for more information on what Steve is talking about.
> 
> While such an installation is initially expensive, the cost in labor-savings of not having to load/unload pigweights on arbors should pay for itself.



Thanks Derek, for the Clancy link, it was something I meant to add.

As commentary to the comments (so far):

- The fly system is a custom, one off, single purchase rig, with partial T rail, totaling about 50 linesets (47 originally and with 3 wire guided arbors added extreme US, now down to 43 ? total counterweighted linesets). I say one off, as the T rail is actually mounted with the T guides (that the arbors glide up and down on) parallel to the SL angled fly tower {exterior building} wall (approx 15 degree off the center line). Thus all the arbors had angled wedges to get the arbor parallel to piaster/plaster line (and to the head blocks, which themselves had to be parallel to the loft blocks) .  The purchase line floor block was not angled quite the same, thus all the purchase lines rub the side of the bottom floor block on the way into the block and coming out of the block. This was a HUGE problem when the purchase lines were hemp as it shredded the rope and you would get rope splinters simply by looking at the rope. It's not as much an issue with plastic rope. This was one of the reasons I Weiss opted to replace the electrics arbors and why it was expensive to do so. 

- It's expensive to motorize and as we really only re-hang our electrics 2-3 times (maybe 4 times) per year, this will never pay for itself in labor savings and it wasn't sold to the managers as such. It IS safer to not have to move weights ("In theory" that should not be as much an issue in a professional house) and as the rigging system does need an overhaul, the portions that replaced aircraft cable, loft block and head blocks, would have had to have happened anyway. We are actually now starting the design for the remainder of the rigging upgrade that will replace the remaining loft blocks - which as a 1950's install, are designed for rope, not aircraft cable. We are also planning on replacing all of the aircraft cable and fittings, but NOT the head blocks and arbors. The head blocks are designed for aircraft cable and are OK and are not custom, thus as we tear down our adjacent 500 seat theater, we will obtain another 50 identical head blocks as spares. The battens/pipes are being replaced - it's now 1.5" schedule 40 steel with non-rated chain and dog-clips (most of them had bolt replacements over the decades). The arbors are staying as they are custom to the space and replacing with custom would run into money we can't afford. 

- The current rigging issue we are dealing with starts with insufficient height of the loading gallery. It's fine for the existing arbors, whose capacity is 660 lbs. The battens are 48 ft. wide in a 39ft proscenium house. The "Murphy" channels, I.E. the 4 channels on the grid (this is not an underhung grid) that have I beams running US/DS and where the loft blocks sit, are essentially one too few and we should have 5. We don't have 5, thus we have only 4 pickup lines for 48ft. pipes (that were original at 40ft.). That makes the pipes bow vertically at the ends, due to poor support. We can add add'l loft blocks external of the Murphy channels (is that the right term ?, that's what I have always heard them called), but then run into issues with the head blocks that only have 4 cable grooves. Plus the arbors only have 4 cable attachment eye-bolts. Changing the head blocks means fewer linesets as they are butt up against ea. other for the most part. Replacing all this (especially adding a pickup line) adds some weight and that requires a longer arbor to retain existing capacity and that makes the arbor longer and then you have insufficient height on the loading gallery to reach/load the bottom of the arbor. 

Another option is keep the quantity of linesets, to stay with 4 pickup lines and use a truss pipe instead of single 1.5" schedule 40 steel. Adding a steel truss pipe to eliminate vertical bowing on the ends results in a reduction of loading capacity on the arbor. A big reduction, so that's out. We have also been told that using a truss pipe, even schedule 40 aluminum, may result in US/DS deflection of the truss, as the "energy" of the load at the ends finds it's path of least resistance, which is US/DS bending. THAT causes interference with adjacent lines sets, which are generally 6" centers, BTW.

The best option might be aluminum (to save weight) as a box design (3"x3" or so) in a welded ladder design to a aluminum schedule 40 pipe welded 2 inches or so below the box. The box prevents the US/DS deflection, with the box plus the pipe creating a rigid structure, eliminating bowing at the ends. Going to aluminum saves weight, BUT NOT MONEY !. The cost of the box/pipe design is such that we may do a few where it counts, such as leg pipes and the US cyc/blackout and other free pipes that get drops that now droop.

Anybody ever deal with these issues before ?. It's not really my responsibility (the PM is dealing with it), but it's all stuff that is fascinating and as with the winch portion, I found it interesting enough as a learning experience that I thought others here might benefit from it.

SB


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## derekleffew (Sep 16, 2009)

SteveB said:


> ... the Murphy channels (is that the right term ?, that's what I have always heard them called), ...


I'd never heard "Murphy channels" before; I believe "loft block wells" is the more commonly-accepted term.


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## RickBoychuk (Jan 6, 2010)

Thern Stage Equipment (TSE) has unveiled the "Brickhouse" counterweight system at LDI this past fall. The Brickhouse arbor is front loading with shelves. The unique configuration of the arbor allows more weight per inch of height, i.e. shorter arbors.

The arbor is used in NBC Studio One which houses the Conan O'Brien Tonight Show. Talk about travel restrictions! And it has been specified in several school districts across the US. There are installations going in in Michigan schools this spring.

See Thern Stage Equipment | Counterweight Systems


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