Sprint Electric helps refurbish the Royal Danish Theatre

  • March 11, 2009
  • Sprint Electric Ltd
  • Case Study
March 11, 2009 - DC drives manufacturer Sprint Electric from Arundel, England, has supplied DC drives for a new stage control system at the historical stage of The Royal Danish Theatre in Copenhagen, Denmark. Located in the heart of Copenhagen, the beautiful ‘Gamle Scene’ – the old stage of The Royal Danish Theatre – was built in 1874 near the site of the original theatre. Last summer, the old stage’s machinery was upgraded and a new control system was installed by Visual Act, an award-winning Swedish company specialized in stage design and technology. One of the advantages of Visual Act's offer was their ability to extend the lives of the existing DC motors by supplying modern intelligent drives from Sprint Electric. Utilizing nearly all of the original motors and maintaining most of the original mechanics, the much needed upgrade could be carried out at a far reduced cost. In addition to the new control electronics for 36 fly bar hoists driven by DC motors, the scope of work included the installation of a stage control system with four portable control desks and redundant servers; upgrading six lighting bridges for increased lifting capacity; installation of four new manually moveable point hoists, and a complete upgrade of the old revolving stage driven by DC motors. “The refurbishing process at The Royal Danish Theatre in Copenhagen was in many ways special and in some ways unique,” says Visual Act’s design engineer Niklas Philipson. “We could build on the experience gained in upgrading the flying system at the Norwegian Theatre in Oslo.” At this project, carried out in only six weeks during the summer break, digital DC drives from Sprint Electric were also used and helped save eight tonnes of cable. “Often the old DC motors are exchanged for AC motors, but we have good experience in keeping them. It is a cost efficient way, as the DC motor drives have very good capacity and durability,” explains Niklas Philipson.For the Royal Danish Theatre’s old stage, new drives and electronics were installed for control of the DC motors on the 36 fly bar winches. To monitor the position of the fly bars, a new arrangement with an angular gear, absolute encoder and limit switch was mounted on each winch. Two Profibus communication channels were provided, one for the drives and one for absolute encoders and safety I/O. The on-board software modules of Sprint Electric’s PLX drives were used extensively to facilitate the complex system and a closed postioning loop was incorporated especially for Visual Act.The six existing lighting bridges were upgraded to increase their load capacity to 800 kg. This involved replacing motors, gearboxes and brakes. New electrical cabinets with servo amplifiers and electronics were also installed. In order to increase safety, slack wire detection was added. Angular gear arrangements similar to those used on the fly bars were installed for the light bridge encoders also. The revolving stage was inspected and fitted with new encoders and a very old motor was removed in order to increase the degree of efficiency and reduce risk of fire. The delivery also included four completely new movable point hoists; the point hoists have individual control cabinets that are electrically similar to the light bridge control cabinets and are also connected to the control system through Profibus. The Visual Act Control System is being installed in more and more theatres throughout Scandinavia and is becoming the new standard in theatrical motion control. The system comes with two types of control desks. The Visual Act Advanced Desk includes a full keyboard and is ergonomically designed for work over longer periods. The second type, Visual Act Touring Desk, uses a touch screen and is more compact and suitable for operation from a variety of locations. At the Royal Danish Theatre two Touring Desks are rail mounted on one of the galleries. The control system operates all movements in the theatre through a combined Profibus and Ethernet network. The networks allow for communication to all devices in the system. The Ethernet is based on the concept of a double redundant ring. A number of hot-swap terminal boxes for the control desks are placed at various points in the stage area. A double emergency stop circuit is connected in series through all the e-stop switches in the system and will cause the system to stop all motion if activated. Sprint Electric’s PLX 4 Q regenerative drives used for the fly bar hoists and the revolving stage are sized between 5 kW (12 amps) and 30 kW (72 amps). They are all fitted with a Profibus communications module and due to the compact size of the PLX the cabinet size could be kept to a minimum to ease the installation of the complete retrofit system.PLX DC drives from Sprint Electric are being used in many other applications where DC drives continue to provide significant advantages over their AC counterparts. PLX drives are designed to offer a powerful, flexible and easy to programme digital DC drive. The drives’ extensive range of application software functions enable difficult tasks to be completed easily and efficiently without costly external hardware. The PLX is part of an integrated range of 2 and 4 quadrant DC drives. The range’s functionality and compact design has proven to be ideal for retrofits when a more cost effective, modern drive system is required. About Sprint Electric: Sprint Electric Ltd., based in Arundel, West Sussex and founded in 1987, offers a wide range of DC motor control devices, with over fifty models covering both single- and three-phase, regenerative and non-regenerative applications. From low voltage servo performance controllers to highly sophisticated fully digital three phase DC variable speed drives of many hundreds of amps, Sprint Electric products meet the demands of countless industrial applications around the globe. Sprint Electric is committed to providing innovative products backed up by a high level of customer service to the world-wide industrial market. In the USA, Sprint Electric products are distributed through Bardac Corp. Learn More

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