Make a table with seven columns and fifteen rows. Label the first column "Specification Type," the second column "Design Specification Requirements," the third column "Servo Motor Specification," the fourth column "Stepper Motor Specifications," the fifth column "Design Weight," the sixth column "Stepper Motor Specification Margin" and the seventh column "Servo Motor Specification Margin."
List in the first column the following specifications: minimum speed, average speed, maximum speed, maximum torque required at the minimum speed, maximum torque required at the average speed, maximum torque required at the maximum speed, average electrical power, maximum power electrical power, cost, mean time between failure and weight in pounds.
Transcribe the specifications for the motor system requirements your motor will need to meet in the second column of the table "Design Specification Requirements."
Transcribe the specifications in the "Design Specifications" column from the stepper motor's data sheet and torque-speed curves into the column labeled "Stepper Motor Specifications."
Transcribe the specifications listed in the "Design Specifications" column from the servo motor's data sheet and torque-speed curves into the column labeled "Servo Motor Specifications."
Weight each of the specifications in terms of importance for your application. Use a weighting scale between 0 and 10 (0 for not important at all and 10 for very important). List the weights in the "Design Weight Column."
Add the weights in the "Design Weight" column. Call the result the "Total Weight."
Multiply the weights in the "Design Weight" column by the difference between the "Design Specification Requirements" and the "Stepper Motor Specifications" for each motor specification used. Record these results in the column labeled "Stepper Motor Weight Differences" Total the stepper motor weight differences and divide this result by the "Total Weight" Call this result the "Stepper Motor Design Score."
Multiply the weights in the "Design Weight" column by the difference between the "Design Specification Requirements" and the "Servo Motor Specifications" for each motor specification used. Record these results in the column labeled "Servo Motor Weight Differences" Total the servo motor weight differences and divide this result by the "Total Weight." Call this result the "Servo Motor Design Score."
Compare the two scores obtained. Conclude that the motor with the higher score is the motor with a larger design specification margin and is the better motor to use.