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Rotronics Frequently Asked Questions


1. Where are Rotronics test benches manufactured?

Rotronics benches are manufactured by the Dynosens company, based in France, Haute Savoie (74). The company is made up of engineers and technicians who design the software, electronic and mechanical components. Part of the manufacturing of the sub-assemblies is handled internally – in the case of all welded structures or software for example – while another part is outsourced. In the final phase, and in all cases, the assembly of benches and the testing operations before delivery to the customer are handled internally. Commissioning and user training tasks are always performed by Dynosens staff including technicians with over 15 years of experience.

2. Who should I contact to repair, replace or upgrade an old Rotronics bench?

Who better than Rotronics, can take care of a Rotronics bench? Regardless of the unrestricted technical possibilities, Rotronics keeps records of every bench sold since 1990 along with its original specifications. Moreover, it would not be unusual for a technician working on old bench to have also taken part in its initial construction! 

3. Can Rotronics work with benches from other brands?

Yes, Rotronics regularly performs work on benches other than its own. In the specific case of old chassis dynamometers for cars and bikes: the Dynascan system allows these test benches to be modernised and give them a new lease of life. 

4. Is it necessary to subscribe to a database to use a Rotronics system?

Absolutely not. The Rotronics software packages are autonomous and can be used indefinitely. Furthermore, in demonstration mode they can be installed an infinite number of times on an infinite number of posts and used for measurements on the bench.

5. What is the true power absorption capacity of the chassis dynamometers and agricultural test benches?

Rotronics dynamometers and agricultural power take-off benches use air-cooled electrical load brakes. Their absorption capacity depends on the rotational speed and the time of use. Another less known parameter is the electronic brake control system which can significantly affect the braking capacity. Rotronics measures the capacity of its test benches on an experimental basis before delivering this information to customers in graph form. Therefore, there are no surprises, the rated absorption capacity is real and it is not just a theoretical braking specification.

6. Can you really test a 1000 hp vehicle on a chassis dynamometer?

In theory yes, as long as the load braking capacity allows. In practice, it is difficult to perform reliable and repeatable measurements on a chassis dynamometer at these power levels. The main obstacle…the vehicle! Although the bank can absorb 1000 hp, the ventilation systems used with the dynamometer are insufficient to cool the vehicle tested at this power level (an internal combustion engine produces as much radiation energy as mechanical energy, without counting the exhaust).[/ toggle]

7. Can the use of a dynamometer, sometimes at high speeds, be dangerous?

When using any kind of dynamometer (car, motorcycle, quad …) the risks are mainly due to rotating parts, running at high speeds and sometimes with considerable inertia. Therefore Rotronics pays particular attention to the safety of the equipment and its users. Rotronics dynamometer test benches comply with European Directive EC 95/1 and are accordingly equipped with protection devices and an emergency stop button, even on the wireless remote systems. However Rotronics goes beyond mere statutory compliance: the protective guards physically prevent access to rotating parts, making it impossible to use the bench if precautions are not taken, with an emergency stop that uses the brake load at maximum power to reduce the stopping time that is already relatively short thanks to Fi technology … All these elements are designed for the greater safety of our customers without hindering their work tasks.

8. What is a look-up table?

A look-up table is a mathematical formula that calculates the resistance to movement of the vehicle according to its speed, i.e., the force applied to it by the road or track. The parameters taken into account are the vehicle mass, the rolling resistance coefficient, the CdA and the slope. Once these parameters are correctly set, the vehicle is subjected to the same resistance on the test bench as on the road. The high performance Rotronics control electronics employ the look-up table very dynamically, even under rapid acceleration. Therefore engines received the right load at the right time, no more overloading turbos at low speed or insufficient resistance at high speed!

9. What is the accuracy of a chassis dynamometer test bench?

The accuracy of the dynamometer obviously depends on the cumulative error of the entire measurement chain but also on the tire/roller connection which is complex in nature. The thoroughness of the test is also a factor: i.e., verifying that all the parameters involved (intake air temperature, engine temperature, warm-up, etc …) are identical in all the tests. It is of course more difficult to maintain the inlet temperature at a constant value than to adjust a parameter on the test bench. Hence the crucial importance of using an accurate test bench with reliable measurements in order to focus on other parameters.

10. Is it necessary to use an accurate test bench just for checking modifications made to an engine (measured before/after)?

Yes, because accuracy does not involve just measuring the power rating announced by the vehicle manufacturer. Accuracy also provides the repeatability of measurements and if the measurements are not repeatable, it is difficult to reliably determine performance gains after modifications.


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