Among the techniques for optimizing a power transmission system is using a dynamometer to monitor the reliability, durability and performance of engines, motors, turbines and other rotary machines.
During the past century, dynamometer devices have taken many forms. Water brake, eddy current, DC, AC and other variations are available. According to Jeff Brown, vice president of Taylor Dynamometers, “The real innovation in dynamometer test systems is in software, instrumentation, data acquisition and control systems.”
Why dynamometers?: Dynamometers are performance-monitoring and testing tools that measure power and acceleration. More sophisticated dynamometer systems collect and measure a multitude of test and engineering variables such as power, torque, speed, temperature, air flow, fuel flow and vibration. Visual and audible alarms indicate when readings fall near or outside the high or low control limits. Advanced systems log and display warnings, and perform predefined shutdown actions when a signal channel indicates failure.
Dynamometer-based tuning and diagnostics help companies to manage the performance of rotating equipment. The devices provide a measurable load, or force, on an engine that closely simulates actual operating conditions. By duplicating normal conditions in a controlled environment, test parameters can be monitored continuously without the influence of external variables. The result is accurate and repeatable data.
Laboratory-grade features are now being incorporated into service level instrumentation, providing a higher level of product at a lower price. Point-and-click interfaces and enhanced graphical reporting tools are providing increased ease of use and improved decisionmaking.
How is the data managed?: Dynamometer data acquisition and control systems can be manual or automatic. Properly executed, tests in manual mode log accurate readings on demand or at specified intervals. Automatic mode provides consistent, repeatable results, and is particularly useful in tests with multiple setpoints.
For example, Taylor Dynamometer’s DynPro control and data acquisition system stores multiple setpoint test profiles that can be retrieved and repeated. The progress screen displays the current step in progress, total time expired and time expired in the current step. Test results are presented online in real time, available in meaningful reports and saved in a searchable database from which data can be exported and viewed in common spreadsheet or word processing programs.
How is the information used?: Dynamometer-based testing systems can be used for ongoing performance monitoring and to diagnose and troubleshoot the source of problems such as low horsepower, low torque, leaks or overheating. Dynamometers support EPA emissions compliance by allowing operators to control exhaust system performance. They support ISO and other quality standards by capturing and printing engine calibrations and mappings. Visibility into low-performing engine types helps companies to make better purchase decisions.
The readings are compared to operator’s manuals or manufacturer’s performance specifications to determine whether the equipment is performing at optimum efficiency. When problems are detected, the initial reading can serve as a baseline when implementing modifications. Subsequent readings reflect the impact of the change and verify that the modification or repair was successful.
What are the most desirable features?: Highly flexible data acquisition and control systems can be used with any dynamometer technology, which simplifies testing and standardizes procedures. Integration with sensors such as smoke opacity meters, emissions gas analyzers and fuel measurement units provide a comprehensive view of the tested equipment.
Highly configurable systems permit the operator to choose what data to log, view, and print or graph. They offer tabular and graphical presentations, data trending, and visibility into peak, average and minimum performance levels. Screens and reports can be configured to personal preferences or specific requirements.
Vendors also are finding ways to reduce the cost of device maintenance. Taylor Dynamometer’s Jeff Brown says, “We used to make our own circuit boards. Now we use commercially available, off-the-shelf circuit boards. This change decreased maintenance costs for our customers and increased parts availability on a global basis.” Dyne System’s Inter-Loc V dynamometer and throttle controller includes optimized connector pinouts to simplify wiring. Dynamic Test Systems’ DynoCom allows enhanced technical support through high speed modems that provide direct communications between DTS systems and the DTS factory.
E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].
