DC drives to give precise control for theatre

Edited by the Engineeringtalk editorial team Jan 9, 2002

A major Swedish theatre has recently installed a new state of the art scenery handling system using 45 Sprint Electric PLX DC drives to give the smooth, precise control required for rapid set changes

A major Swedish theatre has recently installed a new state of the art scenery handling system using 45 Sprint Electric PLX DC drives to give the smooth, precise control required for rapid set changes.

The Upsala Stadsteater is the largest theatre in Uppsala, a historic town to the north of the capital Stockholm in southern Sweden.

The theatre is over 50 years old, and has four stages, the main auditorium seating over 500 people.

It stages a broad range of productions, including Shakespearean classics, modern drama, musical theatre and children's plays.

Upsala Stadsteater stage manager Christer Andersson commissioned the new scenery handling system, which uses Sprint PLX digital drives to replace the original, outdated analogue controls.

The control system was designed by Batalpha, a German company that specialises in theatre management systems, while the motors and drives were integrated and installed by Moeller Electric of Sweden.

Arne Hellberg, the Moeller design engineer responsible for the Upsala Stadsteater, says that the PLX's precise control and high starting torque made them ideal for this unusual application.

"These intelligent digital drives offer many automatic functions, as well as precise control and high starting torque, and combined with the control system they allow the stage manager to change the scenery quickly and safely," Mr Hellberg says.

"Because the control and torque and speed is so good, it is possible to synchronise the simultaneous operation of a number of hoists." The 7.5kW PLX drives are used in the Upsala Stadsteater installation to control the hoists that raise and lower the heavy scenery.

Precise yet rapid changes of scenery require accurate control over the motor speed and high starting torques.

Encoders were used on the motors to provide the accurate positioning required for the scenery.

Unlike some competitors' drives, the standard PLX can accept encoder feedback pulses without the need for additional software or extra cost add-ons.

This is just one of a host of useful features offered by the recently introduced Sprint PLX range of advanced three phase DC drives that are not included on other products.

The PLX is very easy to program using either the four built-in keys and 40-character backlit display or PC-based Windows software.

Unlike comparable DC drives, it comes with a wide selection of the most popular peripheral software blocks at no additional cost.

The 4-quadrant PLX covers the range 5 to 225 kW, while the 2-quadrant PL is available in ratings between 5 and 265 kW.

It is designed to be the most compact, powerful, flexible and easy to use digital DC drive on the market, and is ideally suited to a wide range of demanding applications.

These include the pulp and paper industries, metal processing, rubber and plastic processing, lifting equipment, food, pharmaceutical and chemical manufacturing - as well as theatres!.