PPA's Selection Guide
CEDRAT Piezoelectric Actuators
Direct Piezo Actuators (DPAs) are the most common type of pre-stressed Actuators. They consist of a stack of pre-stressed active material. Conventional DPAs use a serial pre-stress. The level of pre-stress determines the pulling force capability.
A more robust technique (widely used at CEDRAT Technologies in power ultrasonic transducers) consists of a parallel pre-stressed with a bolt-tightened steel rod. However, this approach requires multilayer actuators having ring shape, which are less common and more expensive.
A third alternative consists in pre-stressing the actuator through an external elastic frame, leading to a Parallel Pre-Stressed Actuator, PPA.
DPA and PPAs are solid-state linear Actuators. They use only the expansion of the active material in the "33-mode" thus producing a useful displacement. This displacement is proportional to the voltage on a 170V range. Typically, the Actuator deformation is about 0.1% (1um/mm), so their displacements are limited to about 100um. In counterpart, the forces are naturally large, easily higher than 1kN. DPAs are using a conventional series pre-stress, so they are limited to quasi-static applications such as micro positioning.
|PPA Model Series||PPA M||PPA L||PPA XL|
|Blocking Force [N]||800||3500||7000|
|No-load stroke [µm]||10-40||40-80||40-120|
|Strain Gauge Option||Yes||
|High Temp Option||Yes||Yes||Yes|
|Mech Interface Option||TH||TH||TH|
|Electrical Interface Option||Two wires AWG30||Two wires AWG26||Two wires AWG26|
Examples of some CEDRAT PPA Actuators Series
PPA M Series
PPA L Series
PPA XL Series