6 Starting and Operating
26
Version: 1.1.0
PZ266E
P-88x.x5 Piezo Actuator
6.2
Determining the Operating Parameters
6.2.1
Overview of Limiting Factors
Limiting factors for the operation of the piezo actuator:
Resonant frequency:
The resonant frequency of the piezo actuator serves as a basis for calculating the operating
frequency, which must
not
exceed one third of the resonant frequency. The resonant frequency
according to the data table (p. 39) applies to unclamped operation without load. In an
arrangement with unilateral clamping, the value must be halved.
For
loaded
piezo actuators that are clamped on one side, see "Calculating the Maximum
Operating Frequency of the Loaded Piezo Actuator" (p. 27).
Maximum compressive/tensile stress capacity (p. 41):
The mass of the load to be moved, the preload, and the operating frequency of the piezo
actuator must be selected so that the dynamic forces occurring during operation do not exceed
the maximum compressive/tensile stress capacity of the piezo actuator. See "Calculating the
Forces that Occur During Dynamic Operation" (p. 28).
Maximum permissible operating temperature of the piezo actuator (p. 41):
The greater the operating frequency, the operating voltage (peak-to-peak), and the capacitance
of the piezo actuator, the greater the thermal power generated in the piezo actuator. The
operating frequency, operating voltage and operating time must be selected so that the
maximum permissible operating temperature of the piezo actuator is
not
exceeded. For the
maximum permissible operating frequency without cooling, see column B of the table in
"Maximum Ratings" (p. 40).
It is possible to avoid overheating of the piezo actuator by taking the following measures:
Cooling: Taking measures for cooling increases the threshold values for operating
frequency, operating voltage, and operating time.
Dynamic operation at low frequency only: The maximum operating temperature on the
inside of the piezo actuator can already be exceeded when the temperature measured
on the outside is still within the permissible range.
Peak and average output current of the electronics (p. 11) used:
The electronics must be selected so that it fulfills the following requirements:
The electronics can provide the required current. See "Calculating the Power
Requirement for Sinusoidal Operation" (p. 29).
The output current of the electronics does not exceed the maximum power
consumption of the piezo actuator. See "Maximum Ratings" (p. 40).
The control signal of the electronics does not have steep edges. See "General Notes on
Startup and Operation" (p. 23).