Selecting step motors vs. servo motors

Selection of the optimum motor to use in a motion control application is the first part of a larger motion control system problem. It is the selection segment that usually causes the most problem because the electrical engineer must crossover to the mechanical side of motion to match or select the optimum motor and its associated feedback device. There are many practical constraints that the user or applications engineer must determine in the actual motor selection process. These include the following motor supplier attributes: performance; price; reliability; delivery capability; technical support; reputation/history; system compatibility; documentation; and user friendliness. The performance and price attributes are the major focus of this paper with reliability (in terms of motor-load operation) an important collateral attribute. This paper provides a selection criteria for any type of electric motor that is used in a precision velocity and/or position motion system