The CD-375-250 is the top of the standard CD 375 ladder before the line switches to the longer CDM bodies. Its ±0.250 in (±6.35 mm) full-scale travel is aimed at the jobs where parts actually move several millimetres each cycle - hydraulic rams, press slides, structural joints - rather than the sub-millimetre gauging that the short -025 was built for. The ordering code 010312370000-M is the plain version: no metric core, no Teflon liner, just the catalogue CD-375-250 with the standard #1-72 UNF-2B threaded slug.

What does the work is a linear variable differential transformer. A single primary winding, driven by an a.c. carrier, couples into two secondary windings through a movable iron core. Slide the core and the coupling shifts from one secondary toward the other; wire those secondaries to subtract, and the resulting voltage grows with displacement, reverses sign across the electrical centre, and nulls when the core is balanced. Because the only moving piece is a free slug inside a bore, there is nothing to rub, nothing to wear and no electrical path to the thing being measured - so the device repeats to inside 0.01% of full scale almost indefinitely.

The package is the same 9.5 mm (3/8 in) stainless tube used across the series, but stretched to suit the longer winding: body length runs 1.75 in (44.5 mm) here against 0.50 in on the shortest unit. Glass-filled bobbins hold the coils dimensionally stable with temperature, the stainless shell screens stray a.c. magnetic fields, and the winding pack is sealed to IEC IP-61. Standard rating is -55 °C to +105 °C, with the same series offering high-temperature builds to +200 °C and pressure-sealed shells to 20 kpsi. The CD-375-250 is a live catalogue part; In Fortune stocks and cross-references it for both new designs and the upkeep of equipment already in service.

Note: Figures are read from the TE / Macro Sensors CD 375 datasheet (ENG_DS_CD-CDM_A2), CD-375-250 column. This is the standard inch-core build; operate it only from a differential-input LVDT conditioner and never from a ratiometric front end. Confirm every value against the live datasheet before release.

The shell stays at 0.375 in (9.5 mm) diameter but is the longest in the standard range: dimension A is 1.75 in (44.5 mm), the thread-to-thread span (dimension B) is 1.13 in (28.6 mm), and the coil-centre dimension N is 0.88 in (22.1 mm). The bore that guides the core is held at roughly 0.134 / 0.125 in (3.4 / 3.18 mm), leaving the free slug a small radial clearance so it travels without touching the wall.

Both ends are tapped for mounting and the core itself is threaded #1-72 UNF-2B (the standard inch core on this order) to a depth of at least 0.25 in (6.4 mm); the same locations accept the M2 x 0.4, 6H metric option when ordered as a -006. Because the body is long, plan to clamp it near its centre of length or capture both ends rather than holding it by one tip. The six #32 AWG Teflon-insulated leads, 12 in (305 mm) long, exit from one end.

The sensor brings out six leads: a primary pair to be energised, and two secondary pairs to be read differentially. The conditioner drives the primary and measures the difference between the two secondary voltages, so the secondaries are joined to oppose one another and the output passes through zero at the core's electrical centre.

• YELLOW / BROWN - primary: the excitation pair, fed by the conditioner's oscillator at 3.0 Vrms, 2.5 - 3.0 kHz.
• RED / BLUE - secondary 1: the first pickup winding.
• GREEN / BLACK - secondary 2: the second pickup winding.
• Differential hookup: connect BLUE to GREEN per the datasheet; the displacement signal then appears across RED and BLACK and crosses zero with the core centred.

If your travel is not a quarter inch, move along the CD 375 / CDM 375 ladder: the diameter and the six-lead wiring stay the same while the body length and rated stroke grow together. Shorter members trade travel for more output per millimetre; the longer CDM bodies carry on past half an inch. The standard inch core on this -250 can instead be ordered as a metric core (-006), a Teflon bore (-010), or both (-016) on the ranges where those options apply.

Ordering options: this part is the plain CD-375-250; add -006 for a metric core, -010 for a Teflon bore liner, or -016 for both, where the option is offered (it does not apply to CDM 375-500 or CDM 375-1000). Confirm stroke, body length and core thread before substituting a range.

The CD and CDM LVDT families originate with Macro Sensors, a US specialist in linear variable differential transformers whose catalogue moved into Measurement Specialties and then into TE Connectivity (NYSE: TEL), where the AST position-sensor group now carries them. That long manufacturing history is the reason a single 3/8 in range can be offered from sub-millimetre gauging up to a full inch of travel, with core, bore, temperature and pressure variants on the same mechanical platform.

For the CD-375-250, In Fortune supplies genuine TE / Macro Sensors product with traceable sourcing, and helps select the right stroke and core option across the CD 375 line as well as a matching differential-input signal conditioner.