PrintRVDTs
Kavlico RVDTs are the industry standard for angular and rotary measurements in aviation applications. The lightweight, robust sensors are capable of ±80° angular range in single and multiple channel designs.
RVDTs with integral gear heads are available for applications with higher angular displacements or multiple revolutions.
Typical RVDT applications include:
- Stand-alone airframe and cockpit applications
- Used for integral parts of flight control actuator or servo valve systems
Single Channel RVDTs
A Rotary Variable Differential Transformer (RVDT) is an angular position sensor that produces an output voltage proportional to the angular displacement of a laminated rotor stack. This rotor is mounted on a stainless steel shaft that when rotated, moves the rotor to direct greater flux into one secondary of the stator windings thereby increasing the voltage and reduces the flux in the opposing secondary.
The output wave form is a sine function. A full 360° rotation of the shaft will result in either one or two sine wave cycles depending upon the RVDT design. These different designs are referred to as either single cycle or dual cycle RVDTs. The usable linear range for the single cycle is ±80° around electrical zero. The linear range for the two cycle is ±40° around the zero, with the two cycle exhibiting higher accuracy. These angular sensors typically provide MTBFs higher than any other type of angular sensor.
Multi-Channel RVDTs
When the design of a system requires more electrical redundancy to achieve the necessary system reliability, multi-channel RVDTs are the sensor of choice. This is often the case for military fly-by-wire aircraft.
Up to three separate channels can be placed in tandem inside a common housing. A common shaft will mount three separate rotor stacks each directing flux in different stators mounted in line.
Another multi-channel option is to mount the channels in parallel. This allows a greater number of independent channels in a shorter housing, although the diameter of the total package size must increase. This approach allows for easy replacement of each channel as discrete single channel RVDTs are used to build the multi-channel unit. Each channel is connected to the input shaft via a single anti-backlash gear.
Geared RVDTs
In those cases where many input revolutions must be measured for position such as in trailing edge flap systems, Kavlico can provide a high precision gear head to extend the input range into the thousands of revolutions range.
DC/DC RVDTs
Kavlico manufactures custom DC/DC RVDTs for severe environments. These are designed to order per the end-users application specific requirement.
To find out more about Kavlico sensor solutions, contact us at info@kavlico.com
| Typical Specifications include | The non-contact (brushless) rotor design can operate to 3,000 psi while providing an AC output. |
| Gearheads | Reduction Ratios of up to 4000:1 |
| Excitation Voltage | 1.0 to 26 VRMS |
| Excitation Frequency | 400 to 10,000 Kz |
| Temperature Range | -85°F to +300°F |
| Accuracy | ±0.25% Full Scale |
| Vibration Capability | Stable output up to 80 G’s |
| Accelerated Shock | 50 G’s |
| Ranges | Single Cycle (±80°) or Dual Cycle (±40°) |
