December 2003 - Music theatre Amsterdam

In the course of a modernisation of the electrical equipment of the music theatre Amsterdam also the supply of the lighting cross-beam, which is height adjustable by means of hoisting winches, should be modernised. The present supply was effected by separate cables for the energy supply and cables for the data transfer. The cables had to be manually lowered from and raised back to the attic above the stage. The cable lengths not needed had to be laid on the grid-floor of the attic and thus presented a significant source of accidents.

To eliminate this source of accidents it was decided to realise the new supply by means of 17 motor cable reels of company Stemmann-Technik GmbH.

Special requirements to the motor cable reels are:

1.No data exchange between the motor cable reels and the hoisting gears of the lighting cross-beams.2.The cable tension has to be nearly constant throughout the complete hoist distance.3.It has to be able to operate the motor cable reels in an automatic operation, i.e. the reel movement is adjusting to the hoisting movement of the lighting cross-beam, and in a manual operation, i.e. the cable separated from thelighting cross-beam can be reeled on and off by means of a pushbutton.4.The electrical control has to independently detect whether it has to operate in automatic- or manual operation.5.A combined cable for energy- and data-transfer

Tobe able to realise these rather high demands to the motor cable reelsresp. their drive motors and electrical controls it was not possibleto use the standard drive varieties. Due to this a solution with a servo-motorwith corresponding control was chosen. With this drive solution by meansof the interaction of electrical control and drive motor it is possibleto detect the suspending cable length and preset a certain torque forthe drive motor. By this the constant tensile force could be realised.During manual operation the drive makes it possible to reel the cableon resp. off with a preset constant hoist speed. The automatic change-overfrom manual- to automatic operation is effected by means of insertingthe plug placed at the end of the reelable cable into the lighting cross-beam.During insertion of the plug contacts are actuated which via controlcores in the reelable cable are coupled with the electrical control andthus effect the change-over.

As reelable cable a hybrid-cable is used. The cable isa special production with 5 cores of 25 mm2 for the energy supply, 3cores of 1.5 mm2 for the connection of the electrical control with theplug and 6 optical fibres for the data transmission.

To be able to cover the complete surface of the stagethe motor cable reels are installed in a frame together with the correspondingelectrical controls. The frames are suspended in supports and can bemanually moved. In total 6 of these support tracks with up to 4 motorcable reels are installed above the attic. The electrical current supplytowards the motor cable reels is effected by means of conductor lines.

Notonly the 17 motor cable reels of Stemmann-Technik GmbH are used but thereare also 20 spring-driven cable reels installed in the basement belowthe stage for the supply of movable machines on the stage. Further 10spring-driven cable reels effect the energy- and data supply of the panorama-tripods.The panorama-tripods are base frames for spotlights which are heightadjustably attached to the lateral stage walls.

In the meantime, the measures for modernisation are finishedand the premiere for the cable reels of Stemmann-Technik GmbH was successfullycompleted.