Flat, brushless motor makes light work of Shakespeare

02 August 2010

The RSC Lightlock was developed by Royal Shakespeare Company lighting department head, Vince Herbert, to address a problem that has plagued lighting designers for years – the momentum of heavy, remote-controlled spotlights.

Until now using flexible, lightweight support structures for these lights was out of the question, since attempting to stop would set the whole gantry swinging after each motorised movement, sending spotlights all over the stage and ruining the performance. The only way to use large moving lights was to hang them from heavy-duty mountings, which made accessing the lights a lengthy, dangerous and costly process.

The RSC Lightlock prevents unwanted oscillation on lightweight structures by invoking Newton’s third law of motion – the law of reciprocal actions. When the light needs to stop moving, a heavy counterweight on an internal disc swings in the opposite direction to its movement, nullifying the momentum. This counterweight is rotated by a flat, brushless maxon motor just 90mm in diameter.

The EC 90 Flat was selected for its small size, high performance and precision. If the disc is rotated even slightly too little or too much, the whole principle that makes Lightlock so successful is lost. Even with sudden movements, the unit can cancel out unwanted motion in under two seconds.

RSC Lightlock won a Gold Award for innovation on its public debut at PLASA 08, and the units will now be incorporated into the transformed Royal Shakespeare Theatre, the RSC’s Stratford-Upon-Avon home, scheduled to re-open later this year.