adjustable outward force to meet the design specification of a gap between the turntable and the ring of no more than one-half inch. The six outer ring support wheels are shown circled in the final design in Figure 4. The wheel positions are adjusted after the outer ring is constructed by using an access panel in the ring stage that is filled after the adjustments are complete. To mitigate any contact between the ring and the turntable, a felt strip was glued to the inside edge of the ring and a melamine strip was glued to the outside edge of the turntable. The final design of the web base, central hub and the outer ring supports (circled in purple) are shown in Figure 4. 3. Stage top. The stage top consists of a central hub, 20 turntable interlocking wedges, and 20 ring interlocking wedges. Each of the wedges was formed by gluing two offset ¾-inch plywood segments together and then screwing a circumferential edge to it. The edge was designed to enclose a driving chain. The turntable wedges are fastened in a recessed circumferential ring on the central hub using wood screws. Access panels in the stage top allow for adjustment of the transmission chain tension and for outer ring support alignment. The wedges are shown assembled in Figure 5 and one of the turntable wedges is shown in Figure 6. Figure 7: Steel-cage mounted 3hp induction motor. The spring mounted motor allows the tension in the chain to be changed. The machined aluminum plates stiffened the original motor frame to allow for the axial loads of the chain. 4. Electrical motors and hardware. The design assumptions determined the two motors' power requirements and the sizes of the sprockets used to drive the chains that rotated the ring and turntable. The team measured the coefficient of friction of the casters and determined it to be about 0.014. Using the number of casters (114) and the assumed uniform load distribution, the required power for the turntable is less than 0.25hp and the required power for the ring is slightly greater than 1hp. Both motors used are larger than required but were " free " to the project. The center turntable is driven by a 2hp brushed DC motor furnished by TCU Theatre, and the outer ring is driven by a 3hp AC induction motor that was salvaged from a milling machine. The motors were both controlled by Creative Conners Stagehand controllers with a Showstopper panel for emergency control. The Stagehand controllers require rotary encoders to determine the stages' position and velocity. Our rotary encoders are connected to the motor shafts and each provided electrical signals that allow their respective controllers to determine the motor shaft position and velocity. The DC motor contained an integrated encoder. An incremental quadrature rotary encoder with a line driver differential output signal that was compatible with the Stagehand controller was adapted and mounted to the induction motor's output shaft. The motors are both housed in steel cages that are bolted to the stage surface off stage. A picture of the mounted AC motor is shown in Figure 7. 5. Transmission. The transmission Figure 8: Transmission system drawing showing two chain tensioners and the height shifter necessary to have two separate drive chains and motors. 12 | THEATRE DESIGN & TECHNOLOGY | SPRING 2023 connects the two rotating stages to the motors using chain drives. The chains fit in the wooden channel created on the outer circumference of both the turntable and ring. The friction between the wood and the tensioned chain rotates each piece. The outer ring is connected to the motor