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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 SeriesPPA MPPA LPPA XL
Blocking Force [N] 800 3500 7000
No-load stroke [µm] 10-40 40-80 40-120
Strain Gauge Option Yes

Yes

Yes
Non-Magnetic Option Yes    
High Temp Option Yes Yes Yes
Thermo-Compensated Option      
Mech Interface Option TH TH TH
Electrical Interface Option Two wires AWG30 Two wires AWG26 Two wires AWG26
Notes     Larger actuator

Examples of some CEDRAT PPA Actuators Series


PPA M Series

PPA L Series

PPA XL Series

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