Dynamic braking with traction motors

Retardation with traction motors, either independently or as an adjunct to mechanical braking, has been utilized in various forms on practically all types of electric vehicles from battery trucks to main-line locomotives. In some cases, it is used only to maintain uniform speeds on long grades and in others to make regular service stops. Although the general principles are nearly as old as the electric-traction industry itself, in recent years numerous refinements have greatly extended the usefulness of dynamic braking by affording improved performance, additional safety, and simplification of mechanical-braking systems. This paper discusses the various means by which favorable results have been accomplished, with a minimum amount of additional electric equipment.