GHSAR-750 TE Macro Sensors AC LVDT

The GHSAR-750-TE AC LVDT from Macro Sensors, distributed by Harold G. Schaevitz Industries (HGSI), is a rugged, spring-loaded linear position sensor designed for precise displacement measurement and dimensional gaging in industrial environments. Built around proven Linear Variable Differential Transformer (LVDT) technology, this sensor delivers highly accurate and repeatable position feedback using a non-contact electromagnetic measurement principle.

The GHSAR-750 Series features a compact 3/4-inch diameter stainless steel housing with hermetically sealed coil windings, making it suitable for use in demanding industrial applications where durability and long-term reliability are critical. The radially mounted sealed connector reduces installed length, allowing for easier integration into space-constrained systems while maintaining environmental protection.

Available in measurement ranges from ±0.050 inches up to ±2.00 inches, the GHSAR-750 Series provides flexibility for both precision gaging and general-purpose position sensing applications.

Spring-Loaded Design for Consistent Measurement Contact

The GHSAR-750-TE incorporates a spring-loaded probe shaft that maintains continuous contact with the measured surface. The probe shaft is guided by a precision sleeve bearing and directly coupled to the movable core of the LVDT.

An internal spring applies a nominal force of approximately 6 to 20 ounces depending on the selected measurement range, ensuring stable and repeatable contact without introducing excessive loading on the measured component.

This spring-loaded configuration provides several advantages:

• Consistent probe contact across repeated measurement cycles

• Simplified mechanical installation without complex linkage systems

• Improved repeatability in automated measurement applications

Because the probe is always in controlled contact with the target, measurement variability due to inconsistent engagement is minimized.

AC LVDT Technology

The GHSAR-750-TE operates as an AC LVDT and requires an external signal conditioner for operation. Unlike DC LVDTs that incorporate internal electronics, this sensor uses a purely passive electromagnetic design.

Typical operating parameters include:

• Excitation voltage: 3.0 Vrms nominal

• Excitation frequency: 2.5 to 3.0 kHz

When AC excitation is applied to the primary winding, it creates a magnetic field that induces voltages in two secondary windings. These secondary windings are connected in opposition, and the resulting differential output voltage varies proportionally with the position of the movable core.

A signal conditioner processes this AC output, demodulating the signal and converting it into a usable DC output for system integration.

Advantages of AC LVDT Architecture

The AC LVDT architecture offers several advantages, particularly in industrial applications:

• No internal electronics within the sensor body

• Greater tolerance to temperature extremes compared to integrated sensors

• Ability to locate signal conditioning electronics in a protected environment

• Flexible output configuration depending on the signal conditioner used

Because the sensing element is entirely passive, the sensor is inherently robust and well suited for applications where environmental conditions may be challenging for electronic components.

Non-Contact Measurement Advantages

The GHSAR-750-TE utilizes a non-contact measurement principle, meaning there is no electrical contact between moving and stationary components.

This results in several key benefits:

• No wear mechanisms that degrade signal quality over time

• Consistent performance across millions of cycles

• Minimal maintenance requirements

• Stable output with low long-term drift

Unlike potentiometer-based sensors, which rely on physical contact and can wear over time, the LVDT maintains its performance characteristics throughout its operational life.

Accuracy and Repeatability

The GHSAR-750-TE is designed to provide reliable and repeatable measurement performance:

• Linearity: ≤ ±0.25% of full range output

• Repeatability: ≤ 0.01% of full range output

Repeatability is particularly important in dimensional gaging and quality control applications, where consistent readings across repeated measurements are critical.

The use of a precision sleeve bearing and non-contact sensing ensures that the sensor maintains its performance characteristics even in high-cycle applications.

Hermetically Sealed Stainless Steel Construction

The GHSAR-750-TE is constructed entirely from stainless steel and features hermetically sealed coil windings:

• Coil sealing to IEC IP68 standard

• Sealed connector interface for added protection

This construction provides protection against:

• Moisture and humidity

• Dust and particulate contamination

• Industrial environments where debris or process exposure may occur

The sealed design helps ensure consistent performance and extends the service life of the sensor in demanding applications.

Wide Operating Temperature Range

The GHSAR-750-TE is designed to operate across a broad temperature range:

• Operating temperature: –65°F to +220°F (–55°C to +105°C)

This wide operating range allows the sensor to be used in both controlled environments and more challenging industrial conditions where temperature variations are present.

Flexible Mounting and Compact Design

The GHSAR-750-TE is designed for ease of installation and integration:

• 1/2-20 UNF threaded mounting

• Supplied hex nuts for secure positioning

• Compact 3/4-inch diameter housing

The radially mounted connector reduces the overall installed length compared to axial designs, making the sensor easier to integrate into tight or space-constrained systems.

Interchangeable Contact Tip

The sensor is supplied with an AGD standard No. 9 contact tip made from chrome-plated hardened tool steel.

• Fully interchangeable with other AGD-style tips

• Allows customization for different measurement surfaces and geometries

This flexibility enables the sensor to be adapted to a wide range of measurement tasks without requiring sensor replacement.

Signal Conditioning and Output Options

Because the GHSAR-750-TE is an AC LVDT, it requires an external signal conditioner to convert the AC output into a usable signal.

The signal conditioner performs several functions:

• Provides AC excitation

• Amplifies and demodulates the output signal

• Converts the signal into a standardized output format

Typical output formats include:

• ±10 VDC for bidirectional measurement

• 0–10 VDC for unidirectional systems

• 4–20 mA current loop for noise-resistant transmission

This flexibility allows the sensor to be integrated into a wide range of industrial control, monitoring, and data acquisition systems.

Typical Applications

The GHSAR-750-TE is well suited for a variety of industrial measurement applications, including:

• Industrial gaging systems

• Electronic dial indicators

• Fabricated metal product inspection

• Materials testing equipment

• Large shaft runout (TIR) measurement

Its combination of high repeatability, rugged construction, and flexible integration makes it ideal for both automated and manual measurement systems.