Brakes from Warner Electric are helping to wow
audiences in some of Europe’s largest stage and
theater productions
In many modern stage productions, motion on the set is an intrinsic
part of the magic. Performers fly through the air, stage elements rise
and fall and lighting rigs shift dynamically to suit the action. Since
2013, advanced electric brake systems from Warner Electric, part
of Altra Industrial Motion, have played a quiet but critical role in a
growing number of major theater and stadium shows; working quite
literally behind the scenes.
The challenge for production designers – and for the specialized
companies that build equipment for stage shows and events – is to
create seamless, spectacular effects while ensuring that everything they
do complies with strict industry standards. The widely used German
BGV-C1 regulations, for example, set out the requirements for staging
and production facilities in the entertainment industry (specific items
of equipment, like moving spotlights and flying systems have their
own specific standards too, and some other countries have their own
national norms). BGV-C1 requires moving parts of above stage and
under stage machinery and their loads to be equipped with devices to
protect against inadvertent movements, and for them to be equipped
with devices that can bring the loads to a standstill if a fault occurs.
Electric drive systems for stage machinery are becoming
increasingly popular, allowing designers great freedom to move large
loads and seamlessly coordinate multiple mechanical elements. For
many of these applications, electrically-operated brakes provide a very
effective way to deliver appropriate control capabilities. Designed to
accommodate ‘emergency stop’ requirements and to operate in the
event of a power interruption, these brakes typically use springs to
apply the required braking force, with an electromagnet that, when
energized, overcomes the spring force to allow the brake disc to turn
freely.
For Warner Electric, entry into the world of the theater arose as
a result of its leading position in the supply of electrically-operated
brakes to the elevator market, which has similar requirements for
reliability, rapid actuation and precision control.
“When we looked at theater and stage applications, we identified
a need for a wide range of braking capacities, from 3 Nm up to
5,800 Nm,” explains Bernd Wimmer, the company’s account manager
for the sector. “All these applications require short response times,
silent operation and compliance with the latest directives and norms.”
Warner knew it had access to the technologies that could deliver these
requirements. The company’s advanced damping systems, for example,
use a special foil to minimize noise and vibration, creating brakes that
produce sound emissions as low as 45 dB(A).
Speed and silence are important attributes, but so is control.
The deceleration of stage equipment must be closely managed to
prevent excessive stress on components and to protect performers.
That calls for careful selection of brake size, operating parameters and
friction materials. “Most of the time, brakes are used for static holding
applications, but they have to be able to perform an emergency stop
too, which is a tricky thing to engineer,” explains Wimmer. “A hoist, for
example, could be operating at full speed in an upward direction. When
the drive stops, the inertia of the load means it will continue to move
upwards on the rope, then fall back, creating stress on all connected
components.”
Warner Electric has developed a range of
theatre-specific modular brakes.
And in an environment of highly varied, often one-off,
applications that are typically designed and manufactured to tight
timescales, finding the right solution can be demanding for equipment
makers. “The short lead times and sheer variety of stage applications
makes it very different from the elevator market,” explains Wimmer,
“so we realized we would need a different approach.” That approach
encompasses the whole brake supply chain, from product design to
customer support.
Warner has developed a theater-specific product range, for
example, using modular designs based on its well-proven PK brake
series for lower torque requirements and its FENIX elevator brake
range for high energy applications. The modular brakes are available
with different friction materials and control configurations, and single
or double brake rotors and control circuits, according to the degree of
redundancy required by the application. “Some applications have two
independent brakes, on either side of the gearbox, with two independent
control circuits on each, so there is still a high degree of control
and redundancy in the event of a failure in the gearbox itself,” notes
Wimmer.
To help its customers design the right solution for their
application, Warner’s application engineers offer extensive calculation
support, while the modular design of the brakes allows the chosen
configuration to be assembled quickly and fully factory-tested before
delivery to the customer. Typically, says Wimmer, the whole process
takes eight to twelve weeks from specification to delivery.