Harrison Hydra-Gen was a division of Harrison Equipment Company Inc. which was founded January 1, 1942 by Mr. U.M. (Spec) Harrison, at 1422 San Jacinto Street, Houston, Texas as an electronics component distributor.

In 1969 Schlumberger Well Services approached Harrison to develop a hydraulic driven generator for their oilfield use. This was when Harrison started the journey into mobile hydraulic power generation.

In March of 1996 Harrison Equipment Company, Inc., was sold to The Jackson Electronic Group, Inc., owned primarily by Thomas A. Jackson. Mr. Jackson was interested only in the electronic component distribution business and decided to sell the hydraulic division in its entirety.

James L. Otwell purchased and incorporated Harrison Hydra-Gen, LTD., on January 1, 1997, to engage primarily in the manufacturing and sales of hydraulic driven generators for mobile applications serving the fire apparatus, oilfield and marine markets. Through diligent redesign and work with hydraulic engineers, the hydraulic generator was updated to be smaller, lighter, quieter, and deliver more power.