After working for many years on its authentic electro-hydraulic drive, Timber Lake Playhouse’s revolving stage system obtained vital behind-the-scenes AutomationDirect upgrades in 2007 and 2025.
By Ryan Poethke, ShowFab
Timber Lake Playhouse (TLP), adjoining to its namesake physique of water and surrounded by woods and acres of farmland past, has been working as an expert, non-profit summer season theatre firm in Mt. Carroll, Illinois since 1961. This 371-seat theatre sits on a 10-acre campus, which incorporates housing for its workers, plus the related retailers and administration amenities wanted to placed on a number of performances each summer season. A close-by resort options tent, cabin, and RV tenting, together with extra recreation amenities, offering a readily accessible viewers along with locals or those that may make the journey for the day.
From an engineering perspective, what makes TLP particularly fascinating is its semi-thrust stage—extending into the viewers—that includes a 36-foot diameter part of the ground that rotates below electromechanical management. This transferring flooring, recognized merely as a “revolve” in theatre phrases, permits surroundings to be arrange backstage, then rotated into place for fast scene modifications.
Whereas the essential concept of a revolving stage appears basic, there was vital progress in energy transmission expertise since TLP’s founding over 60 years in the past. Accordingly, the theatre’s revolve has been the recipient {of electrical} and automation upgrades over time to maintain up with the occasions.
Altering Motor Expertise into the 21st Century
Initially, the revolve system was powered by an electro-hydraulic drive, consisting of a 5HP electrical motor because the enter energy supply, driving a hydraulic pump. In flip, the hydraulic fluid was used to function a hydraulic motor which turned the stage by way of a gearbox.
This labored for many years, however by 2007 this multi-part system was turning into unreliable and tough to keep up. As such a important a part of the stage’s operation, this state of affairs was unacceptable. Complicating issues additional, whereas TLP has enough stagehands and technical workers for many day-to-day wants, it was rather more tough to entry specialty technicians on a second’s discover to help a balky stage drive system.
To enhance this example, I volunteered in 2007 to improve the system to full electrical management (Determine 1). Having spent a summer season working on the Playhouse, and now being employed as a controls engineer for ShowFab, which makes a speciality of set constructing and leisure fabrication, I possessed the fitting mixture of expertise and experience wanted to make this improve.
Determine 1a, 1b, 1c, 1d: These pictures present viewers view of the “revolve” stage, in addition to the electrical motor, gearbox, and related pulleys, cables, and tensioning weights, all hidden beneath the theatre’s stage revolve.
The unique hydraulic drive was eliminated. Instead, an electrical-motor-driven gearbox was put in. Pulleys and sheaves, interconnected partially with a steady loop of plane cable and tensioned by weights to determine the required friction, would switch the rotational movement to the stage. This sturdy, and maybe even medieval-looking, mechanical setup is completely unseen by the viewers, and quietly handles the system’s huge torque and reasonable velocity necessities with out taking away from the expertise of the play itself.
Key to the design can be implementing a strategy to management the 240V three-phase electrical motor in each instructions at various speeds, in an easy-to use method. Based mostly on sensible expertise, an AutomationDirect GS2 AC variable frequency drive (VFD) was chosen for the duty. As a result of the location occurred to have electrical energy out there in a considerably unusual 240VAC open delta 3-phase format, the VFD was readily configured to function the motor, with a small user-friendly management panel, to spin the large stage turntable in each a clockwise and counterclockwise route with out problem.
Motor Management Upgrades for 2025
This GS2 drive setup labored nicely for almost twenty years, however time takes its toll on any automation tools. The VFD started experiencing some intermittent faults, which had been simply cleared however created a nuisance for customers. By 2025, the workforce realized it was time for a refit. As soon as once more, I used to be capable of volunteer my time to do that work. As well as, we might take this chance to offer just a few security and efficiency upgrades.
For this improve, I chosen the newest model of the AutomationDirect VFD household, the GS23, which incorporates the identical performance because the older unit but in addition gives many enhanced options.
This contemporary VFD household makes use of three-phase energy just like the now-retired GS2s. However, of particular significance for this mission, the newer VFD also can settle for a single-phase enter to supply a three-phase output wanted for velocity management, ahead/reverse operation, and compatibility with the present motor. The shape issue of the brand new drive intently matches that of the older unit, permitting a brand new enclosure subpanel to be fabricated upfront to help a fast change-out (Determine 2).
Determine 2: AutomationDirect VFDs (a GS2 in 2007, and a GS23 in 2025) have offered easy-to-use stage management for the TLP workforce, and a sensible improve path away from a problematic hydraulic system. The 2025 improve eliminates the continuing want for three-phase energy.
Whereas heavy {industry} generally makes use of three-phase energy to allow superior load carrying capability for a given electrical load, the rotating stage was the final remaining piece of apparatus at TLP that required three-phase energy on the time of this set up. With this new drive in operation, the three-phase requirement may very well be dropped, simplifying the ability’s electrical distribution system.
Enhanced Operator Interface and Security
Along with the VFD panel, the system contains an operator console with a route swap, run/cease buttons, a rotation velocity potentiometer, indicator lights, and a fault reset button; many of those pilot units, the enclosures, and different electrical and wiring parts have been sourced from AutomationDirect (Determine 3).
Determine 3: The operator console proven right here makes use of a number of buttons, lights, and an e-stop button sourced from AutomationDirect to offer a easy means for stagehands to function the stage revolve ahead and backward at various, but affordable, speeds.
Throughout the VFD panel, the newest improve now contains an AutomationDirect ReeR MOSAIC security controller to observe emergency cease (e-stop) buttons positioned at each the operator console and the stage supervisor’s place. If both e-stop button is pressed, the protection controller prompts the VFD’s industry-standard protected torque off (STO) perform, which, as additional defined right here, causes the drive motor to coast to a cease. The protection controller can even help the addition of different e-stop buttons sooner or later, which is a functionality requested by TLP.
One other distinctive function of the design regards how the cooling fan for the VFD enclosure is managed. The aim was to show the fan on each time the VFD is began, after which to proceed to run the fan for a time frame after the VFD is stopped to offer the specified cooling. This may very well be achieved with a hardwired relay, or with a small programmable logic controller (PLC), or by utilizing the PLC perform constructed into the G23 VFD. Nonetheless, on this case it was decided {that a} sensible strategy to obtain this management can be to make use of a security controller auxiliary output. Designers recognize it after they have a number of choices for creating an answer.
The Present Should Go On
Whereas one may say that the center of any theatre firm is the performers and workers, TLP’s distinctive rotating semi-thrust stage setup may very well be thought of the ability’s marquee function. With the ability to rotate between a number of scenes with the push of a button and the flip of a knob provides stage handlers an enormous benefit over having to rapidly shuffle props throughout pauses within the motion. Nonetheless, this perform have to be dependable and maintainable. On this case, two upgrades carried out years aside have progressively enhanced these traits, together with usability.
With these new enhancements, the Timber Lake Playhouse is ready as much as reliably entertain audiences for many years to return, rotating the stage easily in both route for scene transitions. What’s going on behind—or extra actually, beneath—the scenes could also be fascinating to stagehands and engineers, however when every little thing runs easily, the viewers can get misplaced within the story itself, moderately than serious about how the “magical” rotating stage works.
All figures courtesy of Ryan Poethke
Writer Bio
Ryan Poethke works for ShowFab in Fairfield, NJ as the corporate’s controls engineer. ShowFab provides customized fabrication to Broadway, Movie, TV, Museum, High quality Arts, Retail, Experiential Advertising and Cruise Ships industries. Ryan donated his time to assist help Timber Lake Playhouse’s stage revolve mission. He holds a BFA in Theater Design and Expertise from UW-Stevens Level, and an MFA in Technical Manufacturing from Northern Illinois College.
