Abstract
This paper discusses the energy consumption characteristics of electric and pneumatic actuators at reciprocating motion, and then makes a general comparison between the two types of actuator. After determining actuator models with the most used size, energy consumption is investigated at their horizontal and vertical cyclic actuations. It is found that electric actuators need a fixed amount of fundamental power even when they do not move. The fundamental power is used for operating controller and holding load. It is also found that their average efficiency at reciprocating motion is only half of the general specific efficiency of motor. Compared with electric actuators, pneumatic cylinders show a good characteristics that only little of power is consumed for valve driving and air leak at the stopping state. Therefore, when the stop time is relatively long, a pneumatic cylinder is more efficient. It is concluded that it is a misunderstanding to declare that a pneumatic cylinder is certainly inefficient compared with an electric actuator. Actuation condition should be considered when selecting an efficient actuator.
