Stepper motor and driver selection

Figure 1. Pull-out torque and output power for a 57 mm PM stepper driven by a unipolar L/R-driver and a NJM3770A bipolar constant current driver. Stepper motors are used in many different types of applications this makes it difficult to recommend a general step-by-step design flow chart. The design process is more an iterative process, involving experience, calculation and experimentation. The purpose of this application note is to show how system performance is affected by motor and driver selection. Some popular motors and drivers are dealt with, as well as the importance of the gearing between the motor and the load.