AC LVDT Linear Position Sensors PGxR Mild Radiation Resistant Series Power Generation Steam Control Valves

For Use In
Interceptor Valves
Governor Valves
Throttle Valves
Bypass Valves
Stop Valves
AC LVDT Linear Position Sensors PGxR Mild Radiation Resistant Series Power Generation Steam Control Valves
Designed and Engineered for Applications Where Radiation is Present in Power Generating Steam Turbine Control Systems

The Alliance Sensors Group PGxR Series linear sensors are the first LVDT-based valve position sensors designed and engineered specifically for applications in electric power generating steam turbine control systems where radiation is present. Materials selected for the Alliance Sensors Group  PGxR Sensors allow the sensor to survive a dose of 30 Mrads for 40 years. The PGxR series comes in 2 versions- the PGHR heavy duty LVDT and the PGSR super duty LVDT. PGxR Series sensors are available in full ranges of 3 inches 6 inches, 9 inches, 12 inches, and 15 inches.

Also Ideal For Other Heavy Duty Linear Position Sensing Applications

Alliance Sensors Group  PG Series Linear Sensors solve an underlying problem common to most LVDTs found in power gen applications. The problem results from the fact that typical AC-LVDT sensors, currently used for valve position sensing on steam turbines, were never really designed for that type of physically demanding use. The LVDTs mounted on a steam turbine get stepped on, have heavy things dropped on them, are subjected to jets of live steam, etc. Unlike the ordinary LVDTs now in service, the PG series can take this kind of abuse for years on end, providing a new level of reliability in such a rough application, and at comparable costs to typical LVDTs currently in use.

Starting with an aerospace quality LVDT, everything about the Alliance Sensors Group  PG Series linear sensor is heavy duty, from the wire connection terminal block inside an IP-68 sealed housing to the 3/8 inch diameter core rod on the outside, in which the LVDT’s core is encased so that it can never vibrate loose, break off, or fall away. An available in-line ball joint on the connecting rod takes up installation misalignment and a double contact shaft seal keeps dirt and grit out of the sensor’s bore. The wall thickness of the sensor’s housing is from ten and to twenty times as thick as that of typical AC-LVDTs. Electrical connections use Euro-style screw-clamp-type terminals for any size wire from No. 24 to No. 14 AWG, eliminating the nuisance of soldering to misfit connectors. Electrical cables pass through a 3/4-NPS female hub that accepts liquid tight connectors, cord grips, or flexible conduit fittings. A 3/4- to 1/2-NPS female adapter is included.

There has never been anything like the Alliance Sensors Group  PG Series LVDT Linear Sensors for power gen use. Designed and engineered to survive long term in the rough environment of the steam turbine deck, these PG sensors bring a new level of confidence and reliability to this application.

PGRR Series LVDT Linear Sensor:
PGRR Mild Radiation Resistant Super Duty
Range Designators:   Sensitivity:
-0203 3-inch range sensor 0.200 V/V/inch
-0406 6-inch range sensor 0.100 V/V/inch
-0609 9-inch range sensor 0.067 V/V/inch
-0912 12-inch range sensor 0.050 V/V/inch
-1215 15-inch range sensor 0.040 V/V/inch
Electrical Specifications
Excitation Frequency 3 kHz
Excitation Voltage 3 V AC rms nominal
Full Scale Output (S1-S2) 3.5 V ACrms output max from differentially connected secondaries; sum of secondaries output is constant over full range for (A-B)/(A+B) ratiometric operation
P to S Phase shift 10° max
Non-linearity ≤ ±0.3% of FSO nominal (.5% max)
Environmental Specifications
Operating Temperature -40 °C to +175 °C (-40 °F to +350 °F)
Temperature Coefficient ≤ 0.025% FSO/°C
Humidity 95% RH non-condensing
Shock 1000g, 11 msec
  • - Rated for up to 350°F (175°C) operating temperature
  • - Built-in over-temperature indicator for warranty coverage
  • - 3/8 inch diameter core extension rod…twice the diameter of typical LVDTs
  • - Totally enclosed core…cannot vibrate loose, break off or fall away
  • - Double contact shaft seal keeps grit and dirt out of the LVDT’s bore
  • - Inline ball joint on core rod takes up minor installation misalignment
  • - Housing wall 10 to 20 times the thickness of a standard LVDT sensor
  • - Works in 3-wire, 4-wire, 5-wire, and 6-wire systems, and with ratiometric (A-B)/(A+B) signal conditioners requiring a constant sum of the secondaries
  • - Mild radiation-resistant version (30 Mrads for 40 years) available
  • - Electrical connections via Euro-style screw clamp terminal block that takes no. 24 to no. 14 wire…no soldering required
  • - 3/4 NPS female conduit port accepts liquid tight connectors, cord grips, or flexible conduit fittings. 1/2 NPS female conduit adapter supplied with unit
  • - 2-Year warranty…twice as long as the industry standard

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