TL;DR: A Scotch-Yoke dynamometer is the affordable, robust choice for workshops. It tests dampers with sinusoidal motion and generally is accurate, simple, low-maintenance. An electromagnetic (EMA) system costs more but adds programmable motion profiles, wider speed and displacement range. It also delivers higher precision for R&D work. Most service workshops are fully covered by Scotch-Yoke; race teams and manufacturers doing advanced characterization should look at EMA.
There are several types of damper testing machines in the market: Crank-driven, Scotch-Yoke, Hydraulic, and Electromagnetic.
- Crank-driven testers are cheap but their data samples typically require more digital filtering that translates into less detailed test results, that might hides mall changes in damper behavior.
- The Scotch-Yoke shock dyno solves this: it produces clean sinusoidal motion, so the data needs far less filtering and reveals even minor performance changes — while staying affordable.
- Hydraulic testing systems are very powerful and offer extensive testing capabilities but they are very expensive, loud, and dangerous if not maintained properly. Also, they do not meet current environmental requirements.
- Electromagnetic systems match their power and testing capabilities while being quiet, efficient, and more affordable to run.
At LABA7, we focused our resources on developing and perfecting electromagnetic actuated and Scotch-Yoke damper testers as they are superior technologies. They provide excellent accuracy and great value for money.
But how are they different?
- EMA vs Scotch-Yoke at LABA7
- Precision and Control Flexibility
- Speed and Range
- Maintenance
- Power Requirements
EMA vs Scotch-Yoke at LABA7
The Damper Test System EMA and the Scotch-Yoke machines both test shock absorbers, but they differ significantly in mechanism and performance.
EMA offers greater precision, control flexibility, and overall capability, making it suitable for the widest range of testing scenarios — at higher cost and complexity. Scotch-Yoke machines are simpler, more robust, and cheaper, with limits in motion control and versatility. The right choice depends on your testing requirements and budget.
Precision and Control Flexibility
- EMA offers high precision and control over movement, allowing to replicate of real-life conditions in a test environment. The use of an electromagnetic linear actuator and feedback systems enables precise control of velocity, displacement, and force. EMAs can be programmed to simulate a wide variety of motion profiles, including non-sinusoidal waveforms, making them more versatile for different types of shock absorber testing.
- Scotch-Yoke provides only a sinusoidal motion that may not be as easily controlled or adjustable.
Speed and Range
- EMA covers a wide range of speeds and displacements, from very slow to very fast movements, and is typically much more powerful.
- Scotch-Yoke: The speed and force are typically more limited and fixed by the mechanical design.
Maintenance
- EMA has fewer mechanical wear points, so less maintenance over time.
- Scotch-Yoke: The mechanical nature of the Scotch-Yoke can lead to higher wear and tear, requiring more frequent maintenance.
Power Requirements
EMA typically runs on a 3-phase connection, but thanks to its supercapacitor bank it can be configured for a standard 1-phase supply on request. The supercapacitors store energy and deliver the peak power during test runs, so the machine never draws high loads from the grid — and if the power supply is interrupted mid-run, the stored energy is enough to complete the ongoing test.
Scotch-Yoke machines draw power directly from the grid: smaller models run on 1-phase (220/240 VAC), larger models require 3-phase (380/400 VAC).
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