About Us

A Brief History of Our Company 

Drive Source International, Inc. (DSI) acquired the assets of Dynamatic Corporation on February 28, 2002, a manufacturing company steeped in over 75 years of applications knowledge, engineering know-how and the overall world’s leader in Eddy Current drive technology known around the world as Dynamatic® and Ajusto-Spede® variable speed drives and related accessories. 

Winther Motor and Truck Company circa 1921 

Before founding Dynamatic, Martin & Anthony Winthers ran an automobile factory. Martin P. Winther formed Winther Motor and Truck Company in 1916, initially manufacturing a rear-drive Winther truck. Shortly after, the factory manufactured the 4-wheel-drive Winther-Marwin truck, and the Winther passenger car 1920-23. The truck cabs were open and fitted with low doors. Initial capacities were 2,3,4 and 6 tons and were priced from $2,750 to $4,600. Later vehicles extended the line and included trucks in the 1 to 7 ton range. As early as 1919 the company claimed that the Winthers vehicles were the dominating truck in the U.S. Navy. The smaller (1-2 ton) trucks were aimed at the agricultural market, while the heavier models were intended for use in the logging, fire fighting, and snowplowing industries. The latter made early use of rotary plows; one of the largest used two engines, the rear one over the rear axle to drive the truck and the front one for the plow, with the fully-enclosed cab between. In the 1920s, electric starters were added to most vehicles. In 1926, the company produced five vehicle styles ranging from 1 1/2 to 5/7 tons. In its last year the products were renamed Winther-Kenosha, and in the summer of 1927 the plant was sold to H.P. Olsen.  Shortly after, the brothers founded Dynamatic.

Dynamatic Corporation was founded September 12, 1931, in Kenosha, Wisconsin, by Martin and Anthony Winther, in order to manufacture the Winther brother’s invention, the “eddy current clutch”, that was originally intended for automobiles.  The first major application was for air conditioning compressors installed on Pullman railroad cars; this application was the reverse of the usual speed control in that it took the varying speed of the car axle and regulated it to a constant speed output for the compressor.  Approximately 6,900 of these clutches were manufactured.

Pullman Railroad Car Air Conditioner Drive. 

The first commercial Eddy Current drives built in the USA: 1939

The name “Dynamatic” was derived from the words “Dynamo” and “Automatic”, and has become, over the years, a highly recognized and respected trade name in both the U. S. and abroad.

Eddy Current dynamometers were first introduced in 1936.  During the years, 1941 to 1946, the “Dynamatic Corporation’s facilities” were dedicated to the World War II war effort, primarily in the form of dynamometers for aircraft engine testing.

The idea of a variable speed regulated clutch was introduced in 1939, and soon thereafter, the self-contained drive with a motor and variable speed clutch dubbed “Ajusto-Spede”, made its appearance.

In March 1946, the Eaton Manufacturing Company acquired the Dynamatic Corporation, and it remained a wholly owned subsidiary until December 1953, when it became Dynamatic Division of Eaton Corporation.  In the middle ‘60’s, Eaton also developed and manufactured adjustable frequency and DC drives.  In 1995, Eaton completed a consolidation of AF drive manufacture at its Oldsmar, Florida location and sold the Dynamatic Corporation or its Eddy Current business to a group of private investors.  These investors restored the original name to the business, as the Dynamatic Corporation, and continued the manufacture of the full line of Eddy Current drives and controls.  In 2002, the owners of Dynamatic Corporation decided to exit the business and sold the rights to manufacture Eddy Current products to DSI/Dynamatic®.

DSI/Dynamatic’s product line includes air cooled adjustable speed drives, liquid cooled adjustable speed couplings (rated from .25 HP through 2,000 HP), air and liquid cooled brakes, adjustable frequency dynamometers, high speed motors, digital and solid state controllers, inverters and a complete repair operation to rebuild even the original Dynamatic® brand products to their factory original specifications.  Through continuous dedication to the preservation of Eddy Current drives and controls, research and development programs, Dynamatic® brand products today represent a full line of power transmission equipment.