The added weight of the towed vehicle has always made extra braking capacity essential in trailer applications, and electric braking systems have been preferred for this service since the expansion of the industry that began after World War II.
The typical system consists of a hydraulically braked tow vehicle equipped with an electric brake controller that is connected through a wiring harness to the electrically braked trailer.
This paper describes present size ranges and applications of electric brakes and illustrates the most popular type of controller--the hydraulically actuated unit--as well as a self-actuated controller. Auxiliary control units are named, and the advantages of electric brakes are listed.