LVDT position sensors handle high temperatures and harsh conditions

Paul Boughton

Macro Sensors has designed a series of high-temperature and rugged LVDT linear position sensors that can be used in aerospace and defence applications such as fuel/oil level monitoring, load levelling of artillery platforms and controlling flight surfaces of airplanes and rudder positions of aircraft carriers, tankers, ships and submarines. Built to withstand high temperature spikes, the HSTAR 750 Series Hermetically Sealed Position Sensors can withstand the harsh environments common in military aircraft and equipment.
As position feedback components for closed-loop servo systems, these LVDT linear position sensors can serve as single -or multiple-channel devices, depending on redundancy and reliability requirements. Most perform in quad-channel systems for military aircrafts such as the C-17 to the JSF fighter. With the advent of ratiometric LVDTs and digital signal processing techniques, the position sensor has greatly improved in temperature stability and accuracy, thereby ensuring greater precision in fuel monitoring and positioning of aircraft. If these feedback sensors were inaccurate, planes and ships would not follow the optimum path to their destinations, which would result in wasted fuel.
Highly versatile, the HSTAR 750 Series Hermetically Sealed Sensors can also be used with land vehicles such as tanks and trucks, serving as feedback devices on active suspensions for load levelling as well as artillery platform levelling. A combination of these position sensors with hydraulic actuators ensures a firing platform can be precisely levelled very quickly, even while in motion. By combining the high-temperature-resistant linear position sensor with hydraulics and a suitable gyro system to measure roll and yaw, tank canons can 'shoot on the run' rather than having to 'stop and then shoot.'
In addition to these defence applications, the HSTAR LVDT position sensors can be used to monitor moving surfaces such as the skew of flaps of a passenger airliner, or the exhaust nozzle or hydraulic reservoir of a fighter jet. The LVDTs are currently used to monitor the position of the thrust reverser vanes of the 787.
Macro Sensors offers several standard options for the HSTAR 750 sensors, including metric threaded cores, smaller diameters and low-mass cores. If necessary, HSTAR 750 sensors can be constructed for immersion in pressurised fluids and exposure to radiation at 3x107 Rads for 40 years. These 3/4-inch (19 mm) diameter AC-operated linear position sensors are available in ranges of +/-1.25 to +/-250mm (+/-0.050 to +/-10.0inches.
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