### 150V Piezo Ring Stack Actuators

The PiezoDrive SR ring stacks are high performance multilayer actuators with a vacuum compatible polymer coating and a large central aperture. The SR rings stacks are perfectly matched to the range of PiezoDrive amplifiers and driver modules. Applications include: Optics, Microscopy, Nanopositioning, and Precision machining.

### Specifications

 OrderCode Range+/-10% Length OD ID Cap.+/-20% Blocking Force Stiffness Res.Freq. $AU1-20pcs SR080410 14 um 10 mm 8 mm 4.5 mm 0.8 uF 1300 N 130 N/um 150 kHz$AU 88 SR080418 28 um 18 mm 8 mm 4.5 mm 1.6 uF 1300 N 65 N/um 83 kHz $AU 130 SR120610 14 um 10 mm 12 mm 6 mm 2.4 uF 3000 N 220 N/um 150 kHz$AU 128 SR120620 30 um 20 mm 12 mm 6 mm 5.0 uF 3000 N 100 N/um 75 kHz \$AU 260

### Mounting

Stack actuators should not be exposed to significant tensile loads, unequally distributed loads, off-axis loads, bending moments, or torque.

The maximum recommended tensile load is 10% of the blocking force. In applications that require bi-directional forces or high speed motion, a preload force is recommended with a magnitude greater than the maximum tensile load. This gaurantees that the actuator is always in compression. The maximum recommended preload is 50% of the blocking force.

### Range

The range is specified for an applied voltage of -30V to +150V. If the input voltage is unipolar (0V to +150V) the specified range is reduced by a factor of 0.75. When a stack actuator is driving a stiff spring, the range is reduced by the factor $$\frac{k_p}{k_p+k_L}$$ where $$k_p$$ is the actuator stiffness and $$k_L$$ is the load stiffness.

The travel range can also be reduced by restraining the end plates, e.g. by bonding the actuator to a stiff base. This effect is most significant in actuators with a length less than twice the outside diameter.

### Capacitance

The actuator capacitance is the small-signal capacitance measured at room temperature. Due to hysteresis, the effective capacitance increases with applied voltage. When operating at full range, the effective capacitance is approximately twice the small-signal capacitance. The capacitance also increases with temperature. A temperature increase of approximately 50 degrees C will double the effective capacitance.

### Thermal

Piezoelectric actuators dissipate heat when driven at full range with a high frequency. PiezoDrive actuators can be operated continuously at temperatures up to 85 degrees C. Continuous operation beyond this temperature may damage the actuator.

The dissipated heat is approximately 10% of the applied electrical power. For a sine-wave, the applied electrical power is: $$P = \frac{V_{p-p}^2 \pi C f}{4}.$$

### Electrical Current Requirements

Calculate Power Bandwidth

The required current is $$I = C~ dV/dt$$ where $$I$$ is the current, $$C$$ is the effective capacitance, and $$dV/dt$$ is the voltage rate of change. For a sine-wave, the required peak current is equal to: $$I_p = 2 \pi f V_{p-p}$$ where $$V_{p-p}$$ is the peak-to-peak voltage. For a triangle wave, the required peak current is equal to: $$I_p = 2 C f V_{p-p} .$$

### Recommended Drivers

 Amplifier Application PDm200B General purpose, low cost MX200 High Current, Low noise, low cost PDu150 Ultra-low noise PD200 High speed, low noise PX200 High current, low noise

### Connecting Wires

All of the connecting wires are 100mm AWG26 PTFE insulated wires. Other lengths are available on request. Red identifies the positive terminal.

### Vacuum Compatibility

The SA Actuators are supplied with either vacuum compatible polymer encapsulation or a UV cured lacquer coating. Both coatings and the wiring insulation meet the outgassing requirements for NASA SP-R-0022A.

### Options / OEM Customization

• Custom range and dimensions
• Custom wiring arrangement / connectors
• Preload or mechanical amplifier mechanisms

### Piezoelectric Properties

The piezoelectric material is similar to PZT-5H and Navy Type VI.