Topic summary
Dynamic brake
Extracted from the Wikipedia article Dynamic braking.
Blended braking
Although blended braking combines both dynamic and air braking, the resulting braking force is designed to be the same as the air brakes on their own provide. This is achieved by maximizing the dynamic brake portion, and automatically regulating the air brake portion, because the main purpose of dynamic braking is to reduce the amount of air braking required. That conserves air and minimizes the risks of over-heated wheels. One locomotive manufacturer, Electro-Motive Diesel (EMD), estimates that dynamic braking provides between 50% and 70% of the braking force during blended braking.