Selecting a Motor: Selection Procedure

Selecting a motor that satisfies the specifications required by your equipment is an important key to ensuring the desired reliability and economic efficiency of the equipment. This section introduces the procedure to select the ideal motor, selection calculations, key points of selection and selection examples.

An overview of the procedure is explained below.

• Determine the Drive Mechanism
  • First, determine the drive mechanism. Representative drive mechanisms include simple rotating body, ball screw, belt pulley, and rack-and-pinion. Along with the type of drive mechanism, determine the dimensions, mass and coefficient, etc. that are required for the load calculation. The general items are explained below.
    • Dimensions and mass (or density) of load
    • Dimensions and mass (or density) of each part
    • Friction coefficient of the sliding surface of each moving part
• Confirm the Required Specifications
  (Equipment specifications)
  • Check the required specifications for the motor from the equipment specifications. The general items are explained below.
    • Operating speed and operation time
    • Positioning distance and time
    • Resolution
    • Stopping accuracy
    • Position holding
    • Power supply voltage and frequency
    • Operating environment
• Calculate the Load
  • Calculate the values for load torque and load inertia at the motor output shaft. Refer here for the formula to calculate load torque in typical mechanisms.
    Refer here for the formula to calculate inertia in typical shapes.
• Select Motor Type
  • Select the most suitable motor for the required specifications.
• Selection Calculations
  • Determine the most suitable motor after checking that the specifications of the selected motor/gearhead satisfy all of the required specifications, such as mechanical strength, acceleration time and acceleration torque. Since the specific items that must be checked will vary depending on the motor model, refer to the motor selection calculation formulas and selection points.