LVDT for Steam Turbine Power Generation Applications Macro Sensors

Macro Sensors’ HSA 750 Series of 3/4 inch (19 mm) diameter AC-Operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use. The coil windings are sealed against hostile environments to IEC standard IP-68 and electrical termination is through a sealed axial connector. The mating connector plug is supplied with the unit. [read more]

The HSTA 750 Series of 3/4 inch (19 mm) diameter AC-operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for use at high temperatures (400°F) or exposed to mild radiation (3x107 Rads for 40 years). The coil windings are sealed against hostile environments to IEC standard IP-68 and electrical termination is through a sealed axial connector. The mating connector plug is .... [read more]

Macro Sensors’ HSAR 750 Series of 3/4 inch (19 mm) diameter AC-Operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use. The coil windings are sealed against hostile environments to IEC standard IP-68 and electrical termination is through a sealed radial connector located near one end. The mating connector plug is supplied with the unit. [read more]

The HSTAR 750 Series of 3/4 inch (19 mm) diameter AC-operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for use at high temperatures (400°F) or exposed to mild radiation (3x107 Rads for 40 years). The coil windings are sealed against hostile environments to IEC standard ... [read more]

Macro Sensors’ HSE 750 Series of 3/4 inch 19 mm) diameter DC-operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use.... [read more]

Macro Sensors’ HSER 750 Series of 3/4 inch (19 mm) diameter DC-operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use.... [read more]

Macro Sensors’ HLR 750 Series of 3/4 inch diameter high reliability LVDT position sensors are specifically designed for use in gas turbine environments. Rated for operation to 300°F (150°C), these hermetically sealed AC-LVDTs are listed for Class I, Division 2, Groups A, B, C, D and Class I, Zone 2,... [read more]

The HSI 750 Series of loop-powered 4-20 mA sourcing LVDT position transmitters is offered in measuring ranges of 1 to 10 inches (25 to 250 mm) to provide reliable, contactless position monitoring and feedback of control valves and servo actuators. They are rugged and robust devices constructed entirely of TI... [read more]

The Macro Sensors SQ 1250 Series Heavy Duty LVDTs were developed specifically to measure position or motion in mill-type hostile environments. These rugged and reliable contactless sensors, available in measuring ranges from ±0.50 inches to ±10.00 inches, have their electrical assembly totally en... [read more]

THIS MODEL DIRECTLY REPLACES THE LVC-2412 LVDT SIGNAL CONDITIONER.

The Macro Sensors LVC-2500 Signal Conditioner is a single channel signal conditioner that operates on 12 or 24 Volts DC power to support standard LVDT, RVDT, and VRT half-bridge sensors. Designed expressly for use in 24 Volt systems with PLCs and mini-PLCs, or in 12 Volt mobile and vehicular testing systems, it offers the user a choice of three analog outputs: 0 to ±10 V DC, 0 to 10 V DC, or 4 to 20 mA (sourcing) current loop in a 3-wire common ground system in which the power ground is connected to the output signal's ground. [read more]

Prepared by Harold Schaevitz

OEM type LVDTs and VRTs for large and medium steam inlet valve to measure position of stem for pre heating turbine and operation.
Direct OEM replacement LVDTs / LVRTs used for Conditioning valves for large and medium steam turbines.
Direct OEM replacement LVDTs / LVRTs used for reheat and stop valves for large and medium steam turbines.
Direct OEM replacement LVDTs / LVRTs used for throttle valve positioning for large and medium steam turbines.
Direct OEM replacement LVDTs / LVRTs used for feed water boiler pump valve positioning.
Specially designed LVDT for natural gas fuel valve position used for gas turbines for throttle control.
Specially designed LVDT for gas turbine guide vane actuator position feedback for throttle control.
Spring loaded LVDT used for measuring turbine shell expansion.
Special radiation resistant LVDT monitoring hydraulic fluid level in reservoir of feed water pumps in nuclear reactor core.

October 1, 2006

NB:This is the latest revision of a document originally published July 1, 2003. Please discard any previous version.

Many utilities and systems integrators have inquiried of Macro Sensors about whether the LVC 2500 DIN rail mounting LVDT signal conditioning module can be used to operate the many varieties of 3-wire LVRT type linear position sensors commonly used by General Electric for turbine valve monitoring and control in electric power generation plants. The fact is this newest in the line of Macro Sensors DIN-rail mounting LVDT signal conditioners can operate practically all of the 1-1/4 inch diameter, 3-wire LVRTs currently utilized by GE in turbine installations. Although a few very old GE LVRTs (such as the 947D626 series that operates from 24 Volts AC at 50 to 60 Hz) are not compatible, any GE 3-wire LVRT that operates at 3000 Hz, which includes any of the Macro Sensors VRT 1250 series, will work well with the LVC-2500 module. It also works equally well with theMacro Sensors VRT 750 series of 3/4-inch diameter hermetically sealed LVRTs used by some systems integrators and rebuilders to replace OEM GE-style LVRTs, as well as with the 331QMQQT16 series of LVRTs used by Hitachi Ltd. and with any of the LS series of LVRTs (erroneously called LVDTs) by Shinkawa Electric Co., Ltd., which are metricdimensioned equivalents to, or minor variants of, the most often used GE 1-1/4 inch diameter LVRTs.

Most 1-1/4 inch diameter GE-style LVRTs connect to an LVC-2500 module as follows:

LVRT connector pin A (Excitation Low) is connected to signal conditioning module terminal 3
LVRT connector pin B (Output Mid-Tap) is connected to signal conditioning module terminal 7
LVRT connector pin C (Excitation High) is connected to signal conditioning module terminal 4

If the directional sense of the LVRT’s analog output is reversed from that which is required, it can be corrected by interchanging the LVRT’s excitation connections between module terminals 3 and 4.

Certain smaller diameter short stroke GE LVRTs, notably the 128C273 series, and a small number of 1-1/4 inch diameter units have different pinouts or lead wire connections than those of the more common 1-1/4 inch diameter units. The connections to such LVRTs should follow the functional notation in parentheses above, not the pin connections for typical 1-1/4 inch diameter GE LVRTs.

Typical 1-1/4 inch diameter GE LVRTs have connector pins D and E jumpered together internally for use as a connection interlock. These pins would not normally be connected to an LVC-2500 module unless this jumper is being used to disconnect the signal conditioning module from its power source if the LVRT is not connected and/or to notify the PLC or system computer that the LVRT is disconnected and therefore to ignore any input received from the sensor.

The AC output signal of an LVRT is typically lower than for a comparable range LVDT, so if a full ±10 Volts DC output is required, it might be necessary to increase the module’s gain by moving the input gain link jumper inside the module from the default X1 to X2. Do not make this jumper shift unless full output is not attainable using the default. If only unipolar 0-to-10 Volts DC is needed, the default gain link jumper setting (X1) will probably be acceptable, provided the LVRT is first set up using the module’s span
adjustment to give a ±5 Volts DC output and then the module’s zero adjustment is used to shift the -5 Volts DC output up to 0 Volts. This will give an output of 0 to 10 Volts DC. The 4 to 20 mA current loop output setup uses the same general approach, but with the sensor’s mid-position output set at 12 mA instead of 0 Volts. Output is then adjusted with the span control to achieve 4 mA to 20 mA. The guidelines for using long cables from LVRTs to LVC-2500 modules are the same as for LVDTs.

Metric Threaded Cores
Teflon Bore Liners
Smaller Diameter Cores*
Mild Radiation Resistance*

*Not available in all models

Power Supplies for DC LVDT s
Core Extension Rods
Mounting Clamps
LVDT Calibrators
Spare Connectors


HSA 750 Hermetically Sealed AC-LVDT Position Sensors		Macro Sensors’ HSA 750 Series of 3/4 inch (19 mm) diameter AC-Operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use. The coil windings are sealed against hostile environments to IEC standard IP-68 and electrical termination is through a sealed axial connector. The mating connector plug is supplied with the unit. [read more]

HSTA 750 Hermetically Sealed AC-LVDT Position Sensors for High Temperatures		The HSTA 750 Series of 3/4 inch (19 mm) diameter AC-operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for use at high temperatures (400°F) or exposed to mild radiation (3x107 Rads for 40 years). The coil windings are sealed against hostile environments to IEC standard IP-68 and electrical termination is through a sealed axial connector. The mating connector plug is .... [read more]

HSAR 750 Hermetically Sealed AC-LVDT Position Sensors		Macro Sensors’ HSAR 750 Series of 3/4 inch (19 mm) diameter AC-Operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use. The coil windings are sealed against hostile environments to IEC standard IP-68 and electrical termination is through a sealed radial connector located near one end. The mating connector plug is supplied with the unit. [read more]

HSTAR 750 Hermetically Sealed AC-LVDT Position Sensors for High Temperatures		The HSTAR 750 Series of 3/4 inch (19 mm) diameter AC-operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for use at high temperatures (400°F) or exposed to mild radiation (3x107 Rads for 40 years). The coil windings are sealed against hostile environments to IEC standard ... [read more]

HSE 750 Hermetically Sealed DC-LVDT Position Sensors		Macro Sensors’ HSE 750 Series of 3/4 inch 19 mm) diameter DC-operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use.... [read more]

HSER 750 Hermetically Sealed DC-LVDT Position Sensors		Macro Sensors’ HSER 750 Series of 3/4 inch (19 mm) diameter DC-operated LVDTs is designed for a wide range of position measurement applications. These are rugged hermetically sealed sensors, constructed entirely of stainless steel, and intended for general industrial use.... [read more]

HLR 750 Position Sensors for Hazardous Locations		Macro Sensors’ HLR 750 Series of 3/4 inch diameter high reliability LVDT position sensors are specifically designed for use in gas turbine environments. Rated for operation to 300°F (150°C), these hermetically sealed AC-LVDTs are listed for Class I, Division 2, Groups A, B, C, D and Class I, Zone 2,... [read more]

HSI 750 Loop Powered LVDT Position Transmitters		The HSI 750 Series of loop-powered 4-20 mA sourcing LVDT position transmitters is offered in measuring ranges of 1 to 10 inches (25 to 250 mm) to provide reliable, contactless position monitoring and feedback of control valves and servo actuators. They are rugged and robust devices constructed entirely of TI... [read more]

SQ 1250 Heavy Duty LVDT Position Sensors		The Macro Sensors SQ 1250 Series Heavy Duty LVDTs were developed specifically to measure position or motion in mill-type hostile environments. These rugged and reliable contactless sensors, available in measuring ranges from ±0.50 inches to ±10.00 inches, have their electrical assembly totally en... [read more]

LVC 2500 24-Volt DC-Operated LVDT Signal Conditioner		THIS MODEL DIRECTLY REPLACES THE LVC-2412 LVDT SIGNAL CONDITIONER. The Macro Sensors LVC-2500 Signal Conditioner is a single channel signal conditioner that operates on 12 or 24 Volts DC power to support standard LVDT, RVDT, and VRT half-bridge sensors. Designed expressly for use in 24 Volt systems with PLCs and mini-PLCs, or in 12 Volt mobile and vehicular testing systems, it offers the user a choice of three analog outputs: 0 to ±10 V DC, 0 to 10 V DC, or 4 to 20 mA (sourcing) current loop in a 3-wire common ground system in which the power ground is connected to the output signal's ground. [read more]

Common uses of LVDTs in PowerGen Applications	Prepared by Harold Schaevitz	OEM type LVDTs and VRTs for large and medium steam inlet valve to measure position of stem for pre heating turbine and operation. Direct OEM replacement LVDTs / LVRTs used for Conditioning valves for large and medium steam turbines. Direct OEM replacement LVDTs / LVRTs used for reheat and stop valves for large and medium steam turbines. Direct OEM replacement LVDTs / LVRTs used for throttle valve positioning for large and medium steam turbines. Direct OEM replacement LVDTs / LVRTs used for feed water boiler pump valve positioning. Specially designed LVDT for natural gas fuel valve position used for gas turbines for throttle control. Specially designed LVDT for gas turbine guide vane actuator position feedback for throttle control. Spring loaded LVDT used for measuring turbine shell expansion. Special radiation resistant LVDT monitoring hydraulic fluid level in reservoir of feed water pumps in nuclear reactor core.

Macro Sensors LVC-2500 LVDT signal conditioner used with GE-style PowerGen LVRTs	October 1, 2006 NB:This is the latest revision of a document originally published July 1, 2003. Please discard any previous version.	Many utilities and systems integrators have inquiried of Macro Sensors about whether the LVC 2500 DIN rail mounting LVDT signal conditioning module can be used to operate the many varieties of 3-wire LVRT type linear position sensors commonly used by General Electric for turbine valve monitoring and control in electric power generation plants. The fact is this newest in the line of Macro Sensors DIN-rail mounting LVDT signal conditioners can operate practically all of the 1-1/4 inch diameter, 3-wire LVRTs currently utilized by GE in turbine installations. Although a few very old GE LVRTs (such as the 947D626 series that operates from 24 Volts AC at 50 to 60 Hz) are not compatible, any GE 3-wire LVRT that operates at 3000 Hz, which includes any of the Macro Sensors VRT 1250 series, will work well with the LVC-2500 module. It also works equally well with theMacro Sensors VRT 750 series of 3/4-inch diameter hermetically sealed LVRTs used by some systems integrators and rebuilders to replace OEM GE-style LVRTs, as well as with the 331QMQQT16 series of LVRTs used by Hitachi Ltd. and with any of the LS series of LVRTs (erroneously called LVDTs) by Shinkawa Electric Co., Ltd., which are metricdimensioned equivalents to, or minor variants of, the most often used GE 1-1/4 inch diameter LVRTs. Most 1-1/4 inch diameter GE-style LVRTs connect to an LVC-2500 module as follows: LVRT connector pin A (Excitation Low) is connected to signal conditioning module terminal 3 LVRT connector pin B (Output Mid-Tap) is connected to signal conditioning module terminal 7 LVRT connector pin C (Excitation High) is connected to signal conditioning module terminal 4 If the directional sense of the LVRT’s analog output is reversed from that which is required, it can be corrected by interchanging the LVRT’s excitation connections between module terminals 3 and 4. Certain smaller diameter short stroke GE LVRTs, notably the 128C273 series, and a small number of 1-1/4 inch diameter units have different pinouts or lead wire connections than those of the more common 1-1/4 inch diameter units. The connections to such LVRTs should follow the functional notation in parentheses above, not the pin connections for typical 1-1/4 inch diameter GE LVRTs. Typical 1-1/4 inch diameter GE LVRTs have connector pins D and E jumpered together internally for use as a connection interlock. These pins would not normally be connected to an LVC-2500 module unless this jumper is being used to disconnect the signal conditioning module from its power source if the LVRT is not connected and/or to notify the PLC or system computer that the LVRT is disconnected and therefore to ignore any input received from the sensor. The AC output signal of an LVRT is typically lower than for a comparable range LVDT, so if a full ±10 Volts DC output is required, it might be necessary to increase the module’s gain by moving the input gain link jumper inside the module from the default X1 to X2. Do not make this jumper shift unless full output is not attainable using the default. If only unipolar 0-to-10 Volts DC is needed, the default gain link jumper setting (X1) will probably be acceptable, provided the LVRT is first set up using the module’s span adjustment to give a ±5 Volts DC output and then the module’s zero adjustment is used to shift the -5 Volts DC output up to 0 Volts. This will give an output of 0 to 10 Volts DC. The 4 to 20 mA current loop output setup uses the same general approach, but with the sensor’s mid-position output set at 12 mA instead of 0 Volts. Output is then adjusted with the span control to achieve 4 mA to 20 mA. The guidelines for using long cables from LVRTs to LVC-2500 modules are the same as for LVDTs.

Options		Metric Threaded Cores Teflon Bore Liners Smaller Diameter Cores* Mild Radiation Resistance* *Not available in all models

Accessories		Power Supplies for DC LVDT s Core Extension Rods Mounting Clamps LVDT Calibrators Spare Connectors