The Neb600 delivered exactly what the industry demanded—and it quickly became the top choice across the agricultural market.
Its unmatched performance and torque-handling capabilities made it the go-to dynamometer for years. Over the course of my tenure, I oversaw the production of more than 800 Neb600 units, solidifying its status as a benchmark in PTO dynamometer design.
Around 1983, I introduced three new agricultural models: the Neb2-300, Neb4-600, and Neb6-900—later renamed the Neb230, Neb460, and Neb690.
Each received silicon fluid lubrication for improved brake performance. My father’s final patent, U.S. Patent #4483204, was based on the distribution and flow of lubrication to the friction materials—research and development that I had the privilege of leading.
Every AW agricultural dynamometer ever sold—up until the company’s 2002 sale—was manufactured by my business, Colfax Manufacturing Company. My hands-on journey began around 1973–74, when I took responsibility for producing up to 550 units a year. Over the next six years, we built more than 2,700 dynamometers. Across my full tenure with Colfax and AW Dynamometer, we produced and supplied over 5,600 units.
Following my father’s retirement in 1981, and until his passing in 2002, I led both AW Dynamometer and Colfax Mfg. After the 2002 sale of both companies, I remained onboard through the transition period.
Once you’ve spent a lifetime immersed in manufacturing, power testing, and dynamometer design—it never truly leaves you. And so, the question kept returning to me: Could a completely new, innovative Prony brake be created to replace the original 1957 design?
The goal wasn’t to update an old idea—it was to reinvent it. I wanted simpler components, better performance, and a design built for modern demands. The earliest concept struck me on a frigid Illinois night, and I jotted it down on a scrap of cardboard. Years passed, and the idea lay dormant—until my move to Georgia in 2010, when I rediscovered that sketch and reignited the vision.
Designs rarely arrive fully formed. Some iterations failed. But experience—combined with deep familiarity with Prony brake mechanics—guided me as I addressed the old design’s known weaknesses. Though I paused development for a time, the idea showed promise.
Then in March 2012, a new opportunity emerged. Several individuals reached out about developing a next-generation mechanical brake for use in dynamometers. What began as an idea became a focused challenge by May 2012. Over the next nine months, I undertook studies, calculations, and drafted prints—refining every component until a final prototype emerged: a simplified single-rotor-tube Prony brake designed for high horsepower and high torque.
On March 20, 2018, I was awarded U.S. Patent #9,921,117. It marked the beginning of a new era—one rooted in legacy but driven by innovation.
In submitting my patent application, I included several of my father’s original patents as references for the examiner.
Not as a source for reuse—but to underscore the lineage of thought and to affirm that this new design was no mere iteration. It wasn’t a warmed-over modification or a dimensional tweak. It was a ground-up, functionally distinct innovation.
Today, Dyno Tech Services incorporates this patented Prony brake in its next-generation PTO dynamometer series—the DT843 and DT526. This design delivers meaningful advancements in both form and function, including:
These are just a sampling of the improvements driven by this design—deliberately engineered to be a new mousetrap, not an inherited blueprint.
I finished this article on August 1st, 2018—what would have been my father’s 100th birthday. Though he passed in 2002, I know he would have been proud. This work stands not only as an advancement in power testing but also as a tribute to the foundation he laid.
This article is authored by and remains the property of Aaron Warsaw. Reproduction without written permission is not permitted.