Speed and Safety on Roller Coasters

In a Swedish amusement park incremental encoders from Baumer are used to guarantee the highest levels of safety on a roller coaster: they monitor the speed of the carriage’s drive as it approaches the start ramp, even under the toughest conditions

by Noemi Sala

Located in Gothenburg, Liseberg is Sweden’s largest amusement park. Inside there is the Helix roller coaster, with a 1,380 meter track. It hurls its riders at up to 90 km/h through six loops, and exposes them to up to five times their own bodyweight. Half of the riders, Helix takes up to 28, sit facing backwards making the ride even more exciting. Before the start, the riders have to be brought to the start ramp at a height of 41 meters. Controlled asynchronous drives with 315 kW of power are used to move the carriages into the start position. The speed of this drive is recorded by the original Hübner Berlin POG 10 HeavyDuty encoder from Baumer. Moreover, the roller coaster is freely exposed to the elements.

Reliable speed data even under the toughest conditions

The POG 10 incremental HeavyDuty encoder and its sister model, the HOG 10 are part of the HeavyDuty encoders range family. They deliver reliable speed data in a host of potential applications and operate under the toughest conditions. As a result, they help prevent failures and maintain the availability of machines and systems. This saves downtime costs in a host of applications. With the roller coaster, it even makes a valuable contribution to the safety of human life. Here are some HeavyDuty technology specific features. Thanks to solid and generously dimensioned wall thicknesses and a warp-resistant design, the die-cast housings are robust and highly resistant to vibration and shock. Bearings at both encoder shaft ends and the metallic incremental disk offer huge power reserves and high durability through resilience to axial and radial forces. For outdoor use, the anticorrosive properties of the CX category of HeavyDuty encoders to EN ISO 12944, achieved through an optimal choice of material and high-resistant coating, are also very important.

Sealed against dirt, dust and moisture

The combination of labyrinth and shaft seals also protects the inner workings of the HeavyDuty encoders from solid, moist and paste-like contamination. This sealing concept conforms to protection classes IP 66 and IP 67 within a broad temperature range of up to 95 degrees Celsius. Current-insulated bearings ultimately protect the ball bearings of the encoder from current flashovers, and this averts any impairment of the lubricant effect.
The result is an almost indestructible full package that effectively prevents potential malfunctions and failures, even during tough continuous use. This is all the more important as a replacement can get very costly – not because the encoder itself is expensive, but because it is typically mounted in barely accessible locations, as is the case on a roller coaster.

Resilience and precision are essential for the safety

Reliable precision is ensured by the interference-immune scanning function with highly robust, optical circuits (Opto-ASIC). This guarantees optimum electromagnetic compatibility with a burst strength for high-voltage pulses of up to 4 kV. In addition, the Enhanced Monitoring System (EMS) continuously checks numerous encoder functions, swiftly detects connection and encoder errors and transmits the encoder status to the inverter or to the control via an error output. The HeavyDuty encoders achieve the best possible SinCos signal quality through the LowHarmonics technology for excellent control quality, low drive heat-up and high energy efficiency. The incremental square signal outputs also have short-circuit proof, powerful transistor drivers for peak currents of up to 300 mA. They ensure reliable signal quality even over long- distance transmissions of up to 350 meters. These features – resilience and precision – make an important contribution to ensuring that the Gothenburg roller coaster riders are brought to the start ramp safely and at the correct speed.

Rigorous sample tests and full inspections

Baumer guarantees to keep this all-encompassing performance promise every time with original Hübner Berlin technology through rigorous sample tests and by putting each and every HeavyDuty encoder through a full inspection before it leaves the factory.
Resistance to electromagnetic fields, vibration, shocks, dust, hose water, salt spray and much more is ensured on test benches during series production.
Detailed quality certificates confirm that these tests have been passed.