DC Brush Motor White Papers
Once understood, the dc motor constant is a valuable tool for selecting dc motors and generators in a variety of application types
Read—Understanding and Using the DC Motor Constant
The analysis and selection process for dc motors in medical devices with the intent of maximizing battery life by careful selection of motor and gearbox.
Read—-Selecting DC Motors for Battery-Powered Devices 
The analysis and selection process for dc motors in battery-powered device including an explanation of gearbox types and how often the most efficient gearbox is not the optimum choice.
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Battery Powered Devices-Selecting DC Motors-Gearheads 