When making initial design decisions about motor and gearbox/speed reducer types, use these graphs and charts to narrow in on the best types based on your application characterisitics:

Motor Types: Speed vs. Torque Comparison

This graph maps the speed-torque curves of all four standard motor types, using the same scale to clearly illustrate the differences between motors. As an example, note the dramatically higher no-load speed of a Universal motor and the significantly higher starting torques of Permanent Magnet and Brushless DC motors.

Motors: Quick Reference

	Permanent Magnet	AC Induction	Brushless DC	Universal
Voltage	DC	AC	AC, DC (Control)	AC, DC
Speed	1,000 - 5,000	1,350 - 3,400	1,000 - 5,000	8,000 - 20,000+
Horsepower	Medium	Low-Medium	High	Very High
Efficiency	60% - 70%	40% - 80%	65% - 80%	55% - 70%
Life	Medium	Very High	Very High	Low
Maintenance	Medium	Very Low	Very Low	High
Noise	Medium	Quiet	Very Quiet	Noisy
Speed Regulation	Fair	Good	Excellent	Poor
Starting Torque	Very High	Low - Medium	Very High	High

Gearbox-Speed Reducers: Quick Reference

	Planetary	Parallel Shaft	Right Angle
Gears	Spur or Helical	Spur or Helical	Worm Gear	Bevel
Typical Usage	Intermittent	Continuous	Intermittent	Continuous/Intermittent
Max Input Speed	3500	4000	2800	3500
Max Torque	High	Medium	Medium	High
Efficiency	65 - 95	40 - 90	30 - 80	60 - 90
Noise	Low	Medium	Medium	Medium
Limitation	Thermal/Mechanical	Mechanical	Thermal	Mechanical
Back-Driveability	Good	Good	Ratio Dependent	Good